* [PATCH v2 1/6] x86/kgdb: Use IS_ERR_PCPU() macro
2024-12-05 15:40 [PATCH v2 0/6] Enable strict percpu address space checks Uros Bizjak
@ 2024-12-05 15:40 ` Uros Bizjak
2024-12-05 15:40 ` [PATCH v2 2/6] compiler.h: Introduce TYPEOF_UNQUAL() macro Uros Bizjak
` (4 subsequent siblings)
5 siblings, 0 replies; 10+ messages in thread
From: Uros Bizjak @ 2024-12-05 15:40 UTC (permalink / raw)
To: x86, linux-mm, linux-kernel, linux-bcachefs, linux-arch, netdev
Cc: Uros Bizjak, Nadav Amit, Thomas Gleixner, Ingo Molnar,
Borislav Petkov, Dave Hansen, H. Peter Anvin, Dennis Zhou,
Tejun Heo, Christoph Lameter, Linus Torvalds, Andy Lutomirski,
Brian Gerst, Peter Zijlstra
Use IS_ERR_PCPU() when checking the error pointer in the percpu
address space. This macro adds intermediate cast to unsigned long
when switching named address spaces.
The patch will avoid future build errors due to pointer address space
mismatch with enabled strict percpu address space checks.
Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
Acked-by: Nadav Amit <nadav.amit@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Dennis Zhou <dennis@kernel.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: Christoph Lameter <cl@linux.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
---
arch/x86/kernel/kgdb.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/x86/kernel/kgdb.c b/arch/x86/kernel/kgdb.c
index 9c9faa1634fb..102641fd2172 100644
--- a/arch/x86/kernel/kgdb.c
+++ b/arch/x86/kernel/kgdb.c
@@ -655,7 +655,7 @@ void kgdb_arch_late(void)
if (breakinfo[i].pev)
continue;
breakinfo[i].pev = register_wide_hw_breakpoint(&attr, NULL, NULL);
- if (IS_ERR((void * __force)breakinfo[i].pev)) {
+ if (IS_ERR_PCPU(breakinfo[i].pev)) {
printk(KERN_ERR "kgdb: Could not allocate hw"
"breakpoints\nDisabling the kernel debugger\n");
breakinfo[i].pev = NULL;
--
2.42.0
^ permalink raw reply [flat|nested] 10+ messages in thread* [PATCH v2 2/6] compiler.h: Introduce TYPEOF_UNQUAL() macro
2024-12-05 15:40 [PATCH v2 0/6] Enable strict percpu address space checks Uros Bizjak
2024-12-05 15:40 ` [PATCH v2 1/6] x86/kgdb: Use IS_ERR_PCPU() macro Uros Bizjak
@ 2024-12-05 15:40 ` Uros Bizjak
2024-12-05 15:40 ` [PATCH v2 3/6] percpu: Use TYPEOF_UNQUAL() in variable declarations Uros Bizjak
` (3 subsequent siblings)
5 siblings, 0 replies; 10+ messages in thread
From: Uros Bizjak @ 2024-12-05 15:40 UTC (permalink / raw)
To: x86, linux-mm, linux-kernel, linux-bcachefs, linux-arch, netdev
Cc: Uros Bizjak, Nadav Amit, Thomas Gleixner, Dennis Zhou, Tejun Heo,
Christoph Lameter, Linus Torvalds, Andy Lutomirski, Ingo Molnar,
Brian Gerst, Denys Vlasenko, H. Peter Anvin
Define TYPEOF_UNQUAL() to use __typeof_unqual__() as typeof operator
when available, to return unqualified type of the expression.
Current version of sparse doesn't know anything about __typeof_unqual__()
operator. Avoid the usage of __typeof_unqual__() when sparse checking
is active to prevent sparse errors with unknowing keyword.
Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
Acked-by: Nadav Amit <nadav.amit@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Dennis Zhou <dennis@kernel.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: Christoph Lameter <cl@linux.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Peter Zijlstra <peterz@infradead.org
---
include/linux/compiler.h | 13 +++++++++++++
init/Kconfig | 3 +++
2 files changed, 16 insertions(+)
diff --git a/include/linux/compiler.h b/include/linux/compiler.h
index 469a64dd6495..ec0429d7a153 100644
--- a/include/linux/compiler.h
+++ b/include/linux/compiler.h
@@ -321,6 +321,19 @@ static inline void *offset_to_ptr(const int *off)
*/
#define prevent_tail_call_optimization() mb()
+/*
+ * Define TYPEOF_UNQUAL() to use __typeof_unqual__() as typeof
+ * operator when available, to return unqualified type of the exp.
+ *
+ * XXX: Remove test for __CHECKER__ once
+ * sparse learns about __typeof_unqual__.
+ */
+#if defined(CONFIG_CC_HAS_TYPEOF_UNQUAL) && !defined(__CHECKER__)
+# define TYPEOF_UNQUAL(exp) __typeof_unqual__(exp)
+#else
+# define TYPEOF_UNQUAL(exp) __typeof__(exp)
+#endif
+
#include <asm/rwonce.h>
#endif /* __LINUX_COMPILER_H */
diff --git a/init/Kconfig b/init/Kconfig
index a20e6efd3f0f..c1f9eb3d5f2e 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -894,6 +894,9 @@ config ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH
config CC_HAS_INT128
def_bool !$(cc-option,$(m64-flag) -D__SIZEOF_INT128__=0) && 64BIT
+config CC_HAS_TYPEOF_UNQUAL
+ def_bool $(success,echo 'int foo (int a) { __typeof_unqual__(a) b = a; return b; }' | $(CC) -x c - -S -o /dev/null)
+
config CC_IMPLICIT_FALLTHROUGH
string
default "-Wimplicit-fallthrough=5" if CC_IS_GCC && $(cc-option,-Wimplicit-fallthrough=5)
--
2.42.0
^ permalink raw reply [flat|nested] 10+ messages in thread* [PATCH v2 3/6] percpu: Use TYPEOF_UNQUAL() in variable declarations
2024-12-05 15:40 [PATCH v2 0/6] Enable strict percpu address space checks Uros Bizjak
2024-12-05 15:40 ` [PATCH v2 1/6] x86/kgdb: Use IS_ERR_PCPU() macro Uros Bizjak
2024-12-05 15:40 ` [PATCH v2 2/6] compiler.h: Introduce TYPEOF_UNQUAL() macro Uros Bizjak
@ 2024-12-05 15:40 ` Uros Bizjak
2024-12-05 15:40 ` [PATCH v2 4/6] percpu: Use TYPEOF_UNQUAL() in *_cpu_ptr() accessors Uros Bizjak
` (2 subsequent siblings)
5 siblings, 0 replies; 10+ messages in thread
From: Uros Bizjak @ 2024-12-05 15:40 UTC (permalink / raw)
To: x86, linux-mm, linux-kernel, linux-bcachefs, linux-arch, netdev
Cc: Uros Bizjak, Nadav Amit, Dennis Zhou, Tejun Heo,
Christoph Lameter, Andy Lutomirski, Thomas Gleixner, Ingo Molnar,
Borislav Petkov, Dave Hansen, H. Peter Anvin, Kent Overstreet,
Arnd Bergmann, David S. Miller, Eric Dumazet, Jakub Kicinski,
Paolo Abeni, Peter Zijlstra, Will Deacon, Waiman Long,
Boqun Feng, Linus Torvalds, Brian Gerst
Use TYPEOF_UNQUAL() to declare variables as a corresponding
type without named address space qualifier to avoid
"‘__seg_gs’ specified for auto variable ‘var’" errors.
Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
Acked-by: Nadav Amit <nadav.amit@gmail.com>
Cc: Dennis Zhou <dennis@kernel.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: Christoph Lameter <cl@linux.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Kent Overstreet <kent.overstreet@linux.dev>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Jakub Kicinski <kuba@kernel.org>
Cc: Paolo Abeni <pabeni@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Will Deacon <will@kernel.org>
Cc: Waiman Long <longman@redhat.com>
Cc: Boqun Feng <boqun.feng@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Brian Gerst <brgerst@gmail.com>
---
arch/x86/include/asm/percpu.h | 10 +++++-----
fs/bcachefs/util.h | 2 +-
include/asm-generic/percpu.h | 26 +++++++++++++-------------
include/linux/part_stat.h | 2 +-
include/linux/percpu-defs.h | 4 ++--
include/net/snmp.h | 5 ++---
kernel/locking/percpu-rwsem.c | 2 +-
net/mpls/internal.h | 4 ++--
8 files changed, 27 insertions(+), 28 deletions(-)
diff --git a/arch/x86/include/asm/percpu.h b/arch/x86/include/asm/percpu.h
index e525cd85f999..666e4137b09f 100644
--- a/arch/x86/include/asm/percpu.h
+++ b/arch/x86/include/asm/percpu.h
@@ -180,7 +180,7 @@ do { \
__pcpu_type_##size pto_val__ = __pcpu_cast_##size(_val); \
\
if (0) { \
- typeof(_var) pto_tmp__; \
+ TYPEOF_UNQUAL(_var) pto_tmp__; \
pto_tmp__ = (_val); \
(void)pto_tmp__; \
} \
@@ -219,7 +219,7 @@ do { \
__pcpu_type_##size pto_val__ = __pcpu_cast_##size(_val); \
\
if (0) { \
- typeof(_var) pto_tmp__; \
+ TYPEOF_UNQUAL(_var) pto_tmp__; \
pto_tmp__ = (_val); \
(void)pto_tmp__; \
} \
@@ -240,7 +240,7 @@ do { \
(val) == (typeof(val))-1)) ? (int)(val) : 0; \
\
if (0) { \
- typeof(var) pao_tmp__; \
+ TYPEOF_UNQUAL(var) pao_tmp__; \
pao_tmp__ = (val); \
(void)pao_tmp__; \
} \
@@ -273,7 +273,7 @@ do { \
*/
#define raw_percpu_xchg_op(_var, _nval) \
({ \
- typeof(_var) pxo_old__ = raw_cpu_read(_var); \
+ TYPEOF_UNQUAL(_var) pxo_old__ = raw_cpu_read(_var); \
\
raw_cpu_write(_var, _nval); \
\
@@ -287,7 +287,7 @@ do { \
*/
#define this_percpu_xchg_op(_var, _nval) \
({ \
- typeof(_var) pxo_old__ = this_cpu_read(_var); \
+ TYPEOF_UNQUAL(_var) pxo_old__ = this_cpu_read(_var); \
\
do { } while (!this_cpu_try_cmpxchg(_var, &pxo_old__, _nval)); \
\
diff --git a/fs/bcachefs/util.h b/fs/bcachefs/util.h
index fb02c1c36004..415a5803b8f4 100644
--- a/fs/bcachefs/util.h
+++ b/fs/bcachefs/util.h
@@ -586,7 +586,7 @@ do { \
#define per_cpu_sum(_p) \
({ \
- typeof(*_p) _ret = 0; \
+ TYPEOF_UNQUAL(*_p) _ret = 0; \
\
int cpu; \
for_each_possible_cpu(cpu) \
diff --git a/include/asm-generic/percpu.h b/include/asm-generic/percpu.h
index 94cbd50cc870..50597b975a49 100644
--- a/include/asm-generic/percpu.h
+++ b/include/asm-generic/percpu.h
@@ -74,7 +74,7 @@ do { \
#define raw_cpu_generic_add_return(pcp, val) \
({ \
- typeof(pcp) *__p = raw_cpu_ptr(&(pcp)); \
+ TYPEOF_UNQUAL(pcp) *__p = raw_cpu_ptr(&(pcp)); \
\
*__p += val; \
*__p; \
@@ -82,8 +82,8 @@ do { \
#define raw_cpu_generic_xchg(pcp, nval) \
({ \
- typeof(pcp) *__p = raw_cpu_ptr(&(pcp)); \
- typeof(pcp) __ret; \
+ TYPEOF_UNQUAL(pcp) *__p = raw_cpu_ptr(&(pcp)); \
+ TYPEOF_UNQUAL(pcp) __ret; \
__ret = *__p; \
*__p = nval; \
__ret; \
@@ -91,7 +91,7 @@ do { \
#define __cpu_fallback_try_cmpxchg(pcp, ovalp, nval, _cmpxchg) \
({ \
- typeof(pcp) __val, __old = *(ovalp); \
+ TYPEOF_UNQUAL(pcp) __val, __old = *(ovalp); \
__val = _cmpxchg(pcp, __old, nval); \
if (__val != __old) \
*(ovalp) = __val; \
@@ -100,8 +100,8 @@ do { \
#define raw_cpu_generic_try_cmpxchg(pcp, ovalp, nval) \
({ \
- typeof(pcp) *__p = raw_cpu_ptr(&(pcp)); \
- typeof(pcp) __val = *__p, ___old = *(ovalp); \
+ TYPEOF_UNQUAL(pcp) *__p = raw_cpu_ptr(&(pcp)); \
+ TYPEOF_UNQUAL(pcp) __val = *__p, ___old = *(ovalp); \
bool __ret; \
if (__val == ___old) { \
*__p = nval; \
@@ -115,14 +115,14 @@ do { \
#define raw_cpu_generic_cmpxchg(pcp, oval, nval) \
({ \
- typeof(pcp) __old = (oval); \
+ TYPEOF_UNQUAL(pcp) __old = (oval); \
raw_cpu_generic_try_cmpxchg(pcp, &__old, nval); \
__old; \
})
#define __this_cpu_generic_read_nopreempt(pcp) \
({ \
- typeof(pcp) ___ret; \
+ TYPEOF_UNQUAL(pcp) ___ret; \
preempt_disable_notrace(); \
___ret = READ_ONCE(*raw_cpu_ptr(&(pcp))); \
preempt_enable_notrace(); \
@@ -131,7 +131,7 @@ do { \
#define __this_cpu_generic_read_noirq(pcp) \
({ \
- typeof(pcp) ___ret; \
+ TYPEOF_UNQUAL(pcp) ___ret; \
unsigned long ___flags; \
raw_local_irq_save(___flags); \
___ret = raw_cpu_generic_read(pcp); \
@@ -141,7 +141,7 @@ do { \
#define this_cpu_generic_read(pcp) \
({ \
- typeof(pcp) __ret; \
+ TYPEOF_UNQUAL(pcp) __ret; \
if (__native_word(pcp)) \
__ret = __this_cpu_generic_read_nopreempt(pcp); \
else \
@@ -160,7 +160,7 @@ do { \
#define this_cpu_generic_add_return(pcp, val) \
({ \
- typeof(pcp) __ret; \
+ TYPEOF_UNQUAL(pcp) __ret; \
unsigned long __flags; \
raw_local_irq_save(__flags); \
__ret = raw_cpu_generic_add_return(pcp, val); \
@@ -170,7 +170,7 @@ do { \
#define this_cpu_generic_xchg(pcp, nval) \
({ \
- typeof(pcp) __ret; \
+ TYPEOF_UNQUAL(pcp) __ret; \
unsigned long __flags; \
raw_local_irq_save(__flags); \
__ret = raw_cpu_generic_xchg(pcp, nval); \
@@ -190,7 +190,7 @@ do { \
#define this_cpu_generic_cmpxchg(pcp, oval, nval) \
({ \
- typeof(pcp) __ret; \
+ TYPEOF_UNQUAL(pcp) __ret; \
unsigned long __flags; \
raw_local_irq_save(__flags); \
__ret = raw_cpu_generic_cmpxchg(pcp, oval, nval); \
diff --git a/include/linux/part_stat.h b/include/linux/part_stat.h
index ac8c44dd8237..c5e9cac0575e 100644
--- a/include/linux/part_stat.h
+++ b/include/linux/part_stat.h
@@ -33,7 +33,7 @@ struct disk_stats {
#define part_stat_read(part, field) \
({ \
- typeof((part)->bd_stats->field) res = 0; \
+ TYPEOF_UNQUAL((part)->bd_stats->field) res = 0; \
unsigned int _cpu; \
for_each_possible_cpu(_cpu) \
res += per_cpu_ptr((part)->bd_stats, _cpu)->field; \
diff --git a/include/linux/percpu-defs.h b/include/linux/percpu-defs.h
index 35842d1e3879..266297b21a5d 100644
--- a/include/linux/percpu-defs.h
+++ b/include/linux/percpu-defs.h
@@ -320,7 +320,7 @@ static __always_inline void __this_cpu_preempt_check(const char *op) { }
#define __pcpu_size_call_return(stem, variable) \
({ \
- typeof(variable) pscr_ret__; \
+ TYPEOF_UNQUAL(variable) pscr_ret__; \
__verify_pcpu_ptr(&(variable)); \
switch(sizeof(variable)) { \
case 1: pscr_ret__ = stem##1(variable); break; \
@@ -335,7 +335,7 @@ static __always_inline void __this_cpu_preempt_check(const char *op) { }
#define __pcpu_size_call_return2(stem, variable, ...) \
({ \
- typeof(variable) pscr2_ret__; \
+ TYPEOF_UNQUAL(variable) pscr2_ret__; \
__verify_pcpu_ptr(&(variable)); \
switch(sizeof(variable)) { \
case 1: pscr2_ret__ = stem##1(variable, __VA_ARGS__); break; \
diff --git a/include/net/snmp.h b/include/net/snmp.h
index 468a67836e2f..4cb4326dfebe 100644
--- a/include/net/snmp.h
+++ b/include/net/snmp.h
@@ -159,7 +159,7 @@ struct linux_tls_mib {
#define __SNMP_ADD_STATS64(mib, field, addend) \
do { \
- __typeof__(*mib) *ptr = raw_cpu_ptr(mib); \
+ TYPEOF_UNQUAL(*mib) *ptr = raw_cpu_ptr(mib); \
u64_stats_update_begin(&ptr->syncp); \
ptr->mibs[field] += addend; \
u64_stats_update_end(&ptr->syncp); \
@@ -176,8 +176,7 @@ struct linux_tls_mib {
#define SNMP_INC_STATS64(mib, field) SNMP_ADD_STATS64(mib, field, 1)
#define __SNMP_UPD_PO_STATS64(mib, basefield, addend) \
do { \
- __typeof__(*mib) *ptr; \
- ptr = raw_cpu_ptr((mib)); \
+ TYPEOF_UNQUAL(*mib) *ptr = raw_cpu_ptr(mib); \
u64_stats_update_begin(&ptr->syncp); \
ptr->mibs[basefield##PKTS]++; \
ptr->mibs[basefield##OCTETS] += addend; \
diff --git a/kernel/locking/percpu-rwsem.c b/kernel/locking/percpu-rwsem.c
index 6083883c4fe0..d6964fc29f51 100644
--- a/kernel/locking/percpu-rwsem.c
+++ b/kernel/locking/percpu-rwsem.c
@@ -184,7 +184,7 @@ EXPORT_SYMBOL_GPL(__percpu_down_read);
#define per_cpu_sum(var) \
({ \
- typeof(var) __sum = 0; \
+ TYPEOF_UNQUAL(var) __sum = 0; \
int cpu; \
compiletime_assert_atomic_type(__sum); \
for_each_possible_cpu(cpu) \
diff --git a/net/mpls/internal.h b/net/mpls/internal.h
index b9f492ddf93b..83c629529b57 100644
--- a/net/mpls/internal.h
+++ b/net/mpls/internal.h
@@ -33,7 +33,7 @@ struct mpls_dev {
#define MPLS_INC_STATS_LEN(mdev, len, pkts_field, bytes_field) \
do { \
- __typeof__(*(mdev)->stats) *ptr = \
+ TYPEOF_UNQUAL(*(mdev)->stats) *ptr = \
raw_cpu_ptr((mdev)->stats); \
local_bh_disable(); \
u64_stats_update_begin(&ptr->syncp); \
@@ -45,7 +45,7 @@ struct mpls_dev {
#define MPLS_INC_STATS(mdev, field) \
do { \
- __typeof__(*(mdev)->stats) *ptr = \
+ TYPEOF_UNQUAL(*(mdev)->stats) *ptr = \
raw_cpu_ptr((mdev)->stats); \
local_bh_disable(); \
u64_stats_update_begin(&ptr->syncp); \
--
2.42.0
^ permalink raw reply [flat|nested] 10+ messages in thread* [PATCH v2 4/6] percpu: Use TYPEOF_UNQUAL() in *_cpu_ptr() accessors
2024-12-05 15:40 [PATCH v2 0/6] Enable strict percpu address space checks Uros Bizjak
` (2 preceding siblings ...)
2024-12-05 15:40 ` [PATCH v2 3/6] percpu: Use TYPEOF_UNQUAL() in variable declarations Uros Bizjak
@ 2024-12-05 15:40 ` Uros Bizjak
2024-12-05 15:40 ` [PATCH v2 5/6] percpu: Repurpose __percpu tag as a named address space qualifier Uros Bizjak
2024-12-05 15:40 ` [PATCH v2 6/6] percpu/x86: Enable strict percpu checks via named AS qualifiers Uros Bizjak
5 siblings, 0 replies; 10+ messages in thread
From: Uros Bizjak @ 2024-12-05 15:40 UTC (permalink / raw)
To: x86, linux-mm, linux-kernel, linux-bcachefs, linux-arch, netdev
Cc: Uros Bizjak, Nadav Amit, Dennis Zhou, Tejun Heo,
Christoph Lameter, Thomas Gleixner, Ingo Molnar, Borislav Petkov,
Dave Hansen, H. Peter Anvin, Linus Torvalds, Andy Lutomirski,
Brian Gerst, Peter Zijlstra
Use TYPEOF_UNQUAL() macro to declare the return type of *_cpu_ptr()
accessors in the generic named address space to avoid access to
data from pointer to non-enclosed address space type of errors.
Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
Acked-by: Nadav Amit <nadav.amit@gmail.com>
Cc: Dennis Zhou <dennis@kernel.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: Christoph Lameter <cl@linux.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
---
arch/x86/include/asm/percpu.h | 8 ++++++--
include/linux/percpu-defs.h | 2 +-
2 files changed, 7 insertions(+), 3 deletions(-)
diff --git a/arch/x86/include/asm/percpu.h b/arch/x86/include/asm/percpu.h
index 666e4137b09f..27f668660abe 100644
--- a/arch/x86/include/asm/percpu.h
+++ b/arch/x86/include/asm/percpu.h
@@ -73,10 +73,14 @@
unsigned long tcp_ptr__ = raw_cpu_read_long(this_cpu_off); \
\
tcp_ptr__ += (__force unsigned long)(_ptr); \
- (typeof(*(_ptr)) __kernel __force *)tcp_ptr__; \
+ (TYPEOF_UNQUAL(*(_ptr)) __force __kernel *)tcp_ptr__; \
})
#else
-#define arch_raw_cpu_ptr(_ptr) ({ BUILD_BUG(); (typeof(_ptr))0; })
+#define arch_raw_cpu_ptr(_ptr) \
+({ \
+ BUILD_BUG(); \
+ (TYPEOF_UNQUAL(*(_ptr)) __force __kernel *)0; \
+})
#endif
#define PER_CPU_VAR(var) %__percpu_seg:(var)__percpu_rel
diff --git a/include/linux/percpu-defs.h b/include/linux/percpu-defs.h
index 266297b21a5d..2921ea97d242 100644
--- a/include/linux/percpu-defs.h
+++ b/include/linux/percpu-defs.h
@@ -223,7 +223,7 @@ do { \
#define PERCPU_PTR(__p) \
({ \
unsigned long __pcpu_ptr = (__force unsigned long)(__p); \
- (typeof(*(__p)) __force __kernel *)(__pcpu_ptr); \
+ (TYPEOF_UNQUAL(*(__p)) __force __kernel *)(__pcpu_ptr); \
})
#ifdef CONFIG_SMP
--
2.42.0
^ permalink raw reply [flat|nested] 10+ messages in thread* [PATCH v2 5/6] percpu: Repurpose __percpu tag as a named address space qualifier
2024-12-05 15:40 [PATCH v2 0/6] Enable strict percpu address space checks Uros Bizjak
` (3 preceding siblings ...)
2024-12-05 15:40 ` [PATCH v2 4/6] percpu: Use TYPEOF_UNQUAL() in *_cpu_ptr() accessors Uros Bizjak
@ 2024-12-05 15:40 ` Uros Bizjak
2024-12-06 7:35 ` Dennis Zhou
2024-12-05 15:40 ` [PATCH v2 6/6] percpu/x86: Enable strict percpu checks via named AS qualifiers Uros Bizjak
5 siblings, 1 reply; 10+ messages in thread
From: Uros Bizjak @ 2024-12-05 15:40 UTC (permalink / raw)
To: x86, linux-mm, linux-kernel, linux-bcachefs, linux-arch, netdev
Cc: Uros Bizjak, Nadav Amit, Arnd Bergmann, Thomas Gleixner,
Dennis Zhou, Tejun Heo, Christoph Lameter, Linus Torvalds,
Andy Lutomirski, Ingo Molnar, Brian Gerst, H. Peter Anvin,
Peter Zijlstra
The patch introduces per_cpu_qual define and repurposes __percpu
tag as a named address space qualifier using the new define.
Arches can now conditionally define __per_cpu_qual as their
named address space qualifier for percpu variables.
Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
Acked-by: Nadav Amit <nadav.amit@gmail.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Dennis Zhou <dennis@kernel.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: Christoph Lameter <cl@linux.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Peter Zijlstra <peterz@infradead.org>
---
include/asm-generic/percpu.h | 15 +++++++++++++++
include/linux/compiler_types.h | 2 +-
2 files changed, 16 insertions(+), 1 deletion(-)
diff --git a/include/asm-generic/percpu.h b/include/asm-generic/percpu.h
index 50597b975a49..3b93b168faa1 100644
--- a/include/asm-generic/percpu.h
+++ b/include/asm-generic/percpu.h
@@ -6,6 +6,21 @@
#include <linux/threads.h>
#include <linux/percpu-defs.h>
+/*
+ * per_cpu_qual is the qualifier for the percpu named address space.
+ *
+ * Most arches use generic named address space for percpu variables but
+ * some arches define percpu variables in different named address space
+ * (on the x86 arch, percpu variable may be declared as being relative
+ * to the %fs or %gs segments using __seg_fs or __seg_gs named address
+ * space qualifier).
+ */
+#ifdef __per_cpu_qual
+# define per_cpu_qual __per_cpu_qual
+#else
+# define per_cpu_qual
+#endif
+
#ifdef CONFIG_SMP
/*
diff --git a/include/linux/compiler_types.h b/include/linux/compiler_types.h
index 981cc3d7e3aa..877fe0c43c5d 100644
--- a/include/linux/compiler_types.h
+++ b/include/linux/compiler_types.h
@@ -57,7 +57,7 @@ static inline void __chk_io_ptr(const volatile void __iomem *ptr) { }
# define __user BTF_TYPE_TAG(user)
# endif
# define __iomem
-# define __percpu BTF_TYPE_TAG(percpu)
+# define __percpu per_cpu_qual BTF_TYPE_TAG(percpu)
# define __rcu BTF_TYPE_TAG(rcu)
# define __chk_user_ptr(x) (void)0
--
2.42.0
^ permalink raw reply [flat|nested] 10+ messages in thread* Re: [PATCH v2 5/6] percpu: Repurpose __percpu tag as a named address space qualifier
2024-12-05 15:40 ` [PATCH v2 5/6] percpu: Repurpose __percpu tag as a named address space qualifier Uros Bizjak
@ 2024-12-06 7:35 ` Dennis Zhou
2024-12-06 19:07 ` Christoph Lameter (Ampere)
2024-12-06 20:13 ` Uros Bizjak
0 siblings, 2 replies; 10+ messages in thread
From: Dennis Zhou @ 2024-12-06 7:35 UTC (permalink / raw)
To: Uros Bizjak
Cc: x86, linux-mm, linux-kernel, linux-bcachefs, linux-arch, netdev,
Nadav Amit, Arnd Bergmann, Thomas Gleixner, Dennis Zhou,
Tejun Heo, Christoph Lameter, Linus Torvalds, Andy Lutomirski,
Ingo Molnar, Brian Gerst, H. Peter Anvin, Peter Zijlstra
Hi Uros,
On Thu, Dec 05, 2024 at 04:40:55PM +0100, Uros Bizjak wrote:
> The patch introduces per_cpu_qual define and repurposes __percpu
> tag as a named address space qualifier using the new define.
>
> Arches can now conditionally define __per_cpu_qual as their
> named address space qualifier for percpu variables.
>
> Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
> Acked-by: Nadav Amit <nadav.amit@gmail.com>
> Cc: Arnd Bergmann <arnd@arndb.de>
> Cc: Thomas Gleixner <tglx@linutronix.de>
> Cc: Dennis Zhou <dennis@kernel.org>
> Cc: Tejun Heo <tj@kernel.org>
> Cc: Christoph Lameter <cl@linux.com>
> Cc: Linus Torvalds <torvalds@linux-foundation.org>
> Cc: Andy Lutomirski <luto@kernel.org>
> Cc: Ingo Molnar <mingo@kernel.org>
> Cc: Brian Gerst <brgerst@gmail.com>
> Cc: "H. Peter Anvin" <hpa@zytor.com>
> Cc: Peter Zijlstra <peterz@infradead.org>
> ---
> include/asm-generic/percpu.h | 15 +++++++++++++++
> include/linux/compiler_types.h | 2 +-
> 2 files changed, 16 insertions(+), 1 deletion(-)
>
> diff --git a/include/asm-generic/percpu.h b/include/asm-generic/percpu.h
> index 50597b975a49..3b93b168faa1 100644
> --- a/include/asm-generic/percpu.h
> +++ b/include/asm-generic/percpu.h
> @@ -6,6 +6,21 @@
> #include <linux/threads.h>
> #include <linux/percpu-defs.h>
>
> +/*
> + * per_cpu_qual is the qualifier for the percpu named address space.
> + *
> + * Most arches use generic named address space for percpu variables but
> + * some arches define percpu variables in different named address space
> + * (on the x86 arch, percpu variable may be declared as being relative
> + * to the %fs or %gs segments using __seg_fs or __seg_gs named address
> + * space qualifier).
> + */
> +#ifdef __per_cpu_qual
I read through the series and I think my only nit would be here. Can we
name this __percpu_qual? My thoughts are that it keeps it consistent
with the old address space identifier and largely most of the core
percpu stuff is defined with percpu as the naming scheme.
> +# define per_cpu_qual __per_cpu_qual
> +#else
> +# define per_cpu_qual
> +#endif
> +
> #ifdef CONFIG_SMP
>
> /*
> diff --git a/include/linux/compiler_types.h b/include/linux/compiler_types.h
> index 981cc3d7e3aa..877fe0c43c5d 100644
> --- a/include/linux/compiler_types.h
> +++ b/include/linux/compiler_types.h
> @@ -57,7 +57,7 @@ static inline void __chk_io_ptr(const volatile void __iomem *ptr) { }
> # define __user BTF_TYPE_TAG(user)
> # endif
> # define __iomem
> -# define __percpu BTF_TYPE_TAG(percpu)
> +# define __percpu per_cpu_qual BTF_TYPE_TAG(percpu)
> # define __rcu BTF_TYPE_TAG(rcu)
>
> # define __chk_user_ptr(x) (void)0
> --
> 2.42.0
>
Thanks,
Dennis
^ permalink raw reply [flat|nested] 10+ messages in thread* Re: [PATCH v2 5/6] percpu: Repurpose __percpu tag as a named address space qualifier
2024-12-06 7:35 ` Dennis Zhou
@ 2024-12-06 19:07 ` Christoph Lameter (Ampere)
2024-12-06 20:13 ` Uros Bizjak
1 sibling, 0 replies; 10+ messages in thread
From: Christoph Lameter (Ampere) @ 2024-12-06 19:07 UTC (permalink / raw)
To: Dennis Zhou
Cc: Uros Bizjak, x86, linux-mm, linux-kernel, linux-bcachefs,
linux-arch, netdev, Nadav Amit, Arnd Bergmann, Thomas Gleixner,
Tejun Heo, Linus Torvalds, Andy Lutomirski, Ingo Molnar,
Brian Gerst, H. Peter Anvin, Peter Zijlstra
On Thu, 5 Dec 2024, Dennis Zhou wrote:
> I read through the series and I think my only nit would be here. Can we
> name this __percpu_qual? My thoughts are that it keeps it consistent
> with the old address space identifier and largely most of the core
> percpu stuff is defined with percpu as the naming scheme.
Yes lets keep it consistent.
^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: [PATCH v2 5/6] percpu: Repurpose __percpu tag as a named address space qualifier
2024-12-06 7:35 ` Dennis Zhou
2024-12-06 19:07 ` Christoph Lameter (Ampere)
@ 2024-12-06 20:13 ` Uros Bizjak
1 sibling, 0 replies; 10+ messages in thread
From: Uros Bizjak @ 2024-12-06 20:13 UTC (permalink / raw)
To: Dennis Zhou
Cc: x86, linux-mm, linux-kernel, linux-bcachefs, linux-arch, netdev,
Nadav Amit, Arnd Bergmann, Thomas Gleixner, Tejun Heo,
Christoph Lameter, Linus Torvalds, Andy Lutomirski, Ingo Molnar,
Brian Gerst, H. Peter Anvin, Peter Zijlstra
On Fri, Dec 6, 2024 at 8:35 AM Dennis Zhou <dennis@kernel.org> wrote:
>
> Hi Uros,
>
> On Thu, Dec 05, 2024 at 04:40:55PM +0100, Uros Bizjak wrote:
> > The patch introduces per_cpu_qual define and repurposes __percpu
> > tag as a named address space qualifier using the new define.
> >
> > Arches can now conditionally define __per_cpu_qual as their
> > named address space qualifier for percpu variables.
> >
> > Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
> > Acked-by: Nadav Amit <nadav.amit@gmail.com>
> > Cc: Arnd Bergmann <arnd@arndb.de>
> > Cc: Thomas Gleixner <tglx@linutronix.de>
> > Cc: Dennis Zhou <dennis@kernel.org>
> > Cc: Tejun Heo <tj@kernel.org>
> > Cc: Christoph Lameter <cl@linux.com>
> > Cc: Linus Torvalds <torvalds@linux-foundation.org>
> > Cc: Andy Lutomirski <luto@kernel.org>
> > Cc: Ingo Molnar <mingo@kernel.org>
> > Cc: Brian Gerst <brgerst@gmail.com>
> > Cc: "H. Peter Anvin" <hpa@zytor.com>
> > Cc: Peter Zijlstra <peterz@infradead.org>
> > ---
> > include/asm-generic/percpu.h | 15 +++++++++++++++
> > include/linux/compiler_types.h | 2 +-
> > 2 files changed, 16 insertions(+), 1 deletion(-)
> >
> > diff --git a/include/asm-generic/percpu.h b/include/asm-generic/percpu.h
> > index 50597b975a49..3b93b168faa1 100644
> > --- a/include/asm-generic/percpu.h
> > +++ b/include/asm-generic/percpu.h
> > @@ -6,6 +6,21 @@
> > #include <linux/threads.h>
> > #include <linux/percpu-defs.h>
> >
> > +/*
> > + * per_cpu_qual is the qualifier for the percpu named address space.
> > + *
> > + * Most arches use generic named address space for percpu variables but
> > + * some arches define percpu variables in different named address space
> > + * (on the x86 arch, percpu variable may be declared as being relative
> > + * to the %fs or %gs segments using __seg_fs or __seg_gs named address
> > + * space qualifier).
> > + */
> > +#ifdef __per_cpu_qual
>
> I read through the series and I think my only nit would be here. Can we
> name this __percpu_qual? My thoughts are that it keeps it consistent
> with the old address space identifier and largely most of the core
> percpu stuff is defined with percpu as the naming scheme.
I based the approach on the definition of per_cpu_offset() a few lines
bellow in include/asm-generic/percpu.h:
--q--
#ifndef __per_cpu_offset
extern unsigned long __per_cpu_offset[NR_CPUS];
#define per_cpu_offset(x) (__per_cpu_offset[x])
#endif
--/q--
Sure, we can call this __percpu_qual. So, the definition in
arch/x86/include/asm/percpu.h would read as:
# define __percpu_qual __percpu_seg_override
> > +# define per_cpu_qual __per_cpu_qual
> > +#else
> > +# define per_cpu_qual
> > +#endif
The above part could be recoded as:
#ifndef __percpu_qual
# define __percpu_qual
#endif
while the line below would become:
# define __percpu __percpu_qual BTF_TYPE_TAG(percpu)
> > +
> > #ifdef CONFIG_SMP
> >
> > /*
> > diff --git a/include/linux/compiler_types.h b/include/linux/compiler_types.h
> > index 981cc3d7e3aa..877fe0c43c5d 100644
> > --- a/include/linux/compiler_types.h
> > +++ b/include/linux/compiler_types.h
> > @@ -57,7 +57,7 @@ static inline void __chk_io_ptr(const volatile void __iomem *ptr) { }
> > # define __user BTF_TYPE_TAG(user)
> > # endif
> > # define __iomem
> > -# define __percpu BTF_TYPE_TAG(percpu)
> > +# define __percpu per_cpu_qual BTF_TYPE_TAG(percpu)
> > # define __rcu BTF_TYPE_TAG(rcu)
> >
> > # define __chk_user_ptr(x) (void)0
Let me test these changes a bit, I'll send a v3 in a couple of days.
Thanks,
Uros.
^ permalink raw reply [flat|nested] 10+ messages in thread
* [PATCH v2 6/6] percpu/x86: Enable strict percpu checks via named AS qualifiers
2024-12-05 15:40 [PATCH v2 0/6] Enable strict percpu address space checks Uros Bizjak
` (4 preceding siblings ...)
2024-12-05 15:40 ` [PATCH v2 5/6] percpu: Repurpose __percpu tag as a named address space qualifier Uros Bizjak
@ 2024-12-05 15:40 ` Uros Bizjak
5 siblings, 0 replies; 10+ messages in thread
From: Uros Bizjak @ 2024-12-05 15:40 UTC (permalink / raw)
To: x86, linux-mm, linux-kernel, linux-bcachefs, linux-arch, netdev
Cc: Uros Bizjak, Nadav Amit, Dennis Zhou, Tejun Heo,
Christoph Lameter, Thomas Gleixner, Ingo Molnar, Borislav Petkov,
Dave Hansen, H. Peter Anvin, Linus Torvalds, Andy Lutomirski,
Brian Gerst, Peter Zijlstra
This patch declares percpu variables in __seg_gs/__seg_fs named AS
and keeps them named AS qualified until they are dereferenced with
percpu accessor. This approach enables various compiler check
for cross-namespace variable assignments.
Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
Acked-by: Nadav Amit <nadav.amit@gmail.com>
Cc: Dennis Zhou <dennis@kernel.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: Christoph Lameter <cl@linux.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
---
v2: - Add comment to remove test for __CHECKER__ once sparse learns
about __typeof_unqual__.
---
arch/x86/include/asm/percpu.h | 20 +++++++++++++++++---
1 file changed, 17 insertions(+), 3 deletions(-)
diff --git a/arch/x86/include/asm/percpu.h b/arch/x86/include/asm/percpu.h
index 27f668660abe..6be1eafa76ec 100644
--- a/arch/x86/include/asm/percpu.h
+++ b/arch/x86/include/asm/percpu.h
@@ -95,9 +95,23 @@
#endif /* CONFIG_SMP */
-#define __my_cpu_type(var) typeof(var) __percpu_seg_override
-#define __my_cpu_ptr(ptr) (__my_cpu_type(*(ptr))*)(__force uintptr_t)(ptr)
-#define __my_cpu_var(var) (*__my_cpu_ptr(&(var)))
+/*
+ * XXX: Remove test for __CHECKER__ once
+ * sparse learns about __typeof_unqual__.
+ */
+#if defined(CONFIG_USE_X86_SEG_SUPPORT) && \
+ defined(CONFIG_CC_HAS_TYPEOF_UNQUAL) && !defined(__CHECKER__)
+# define __my_cpu_type(var) typeof(var)
+# define __my_cpu_ptr(ptr) (ptr)
+# define __my_cpu_var(var) (var)
+
+# define __per_cpu_qual __percpu_seg_override
+#else
+# define __my_cpu_type(var) typeof(var) __percpu_seg_override
+# define __my_cpu_ptr(ptr) (__my_cpu_type(*(ptr))*)(__force uintptr_t)(ptr)
+# define __my_cpu_var(var) (*__my_cpu_ptr(&(var)))
+#endif
+
#define __percpu_arg(x) __percpu_prefix "%" #x
#define __force_percpu_arg(x) __force_percpu_prefix "%" #x
--
2.42.0
^ permalink raw reply [flat|nested] 10+ messages in thread