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imf15.hostedemail.com; dkim=none; dmarc=none; spf=pass (imf15.hostedemail.com: domain of alex@ghiti.fr designates 217.70.183.193 as permitted sender) smtp.mailfrom=alex@ghiti.fr ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1691315638; a=rsa-sha256; cv=none; b=Qo42BsGGV63xCkiW4iZlF7yKrc4q8YLYWbWLjv0TbZIw3lzcXoOgx1wPMBis3GMLpFNuxF wnKK2j93jw4+F1S0vPPMU3PV66i8ODYzpv5fFkE7hsRMyeYyYlPbOw2kZ7dukLhK2zn52q aIZ9nL0QMfIawA3oMzliAk0eFzOCXGU= Received: by mail.gandi.net (Postfix) with ESMTPSA id D0277240005; Sun, 6 Aug 2023 09:53:51 +0000 (UTC) Message-ID: <4c692993-86ab-fdce-8c78-f676cf90e861@ghiti.fr> Date: Sun, 6 Aug 2023 11:53:51 +0200 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.13.0 Subject: Re: [PATCH v8 1/4] RISC-V: mm: Restrict address space for sv39,sv48,sv57 Content-Language: en-US To: Charlie Jenkins , linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org Cc: conor@kernel.org, paul.walmsley@sifive.com, palmer@rivosinc.com, aou@eecs.berkeley.edu, anup@brainfault.org, konstantin@linuxfoundation.org, linux-doc@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-mm@kvack.org, mick@ics.forth.gr, jrtc27@jrtc27.com, rdunlap@infradead.org, alexghiti@rivosinc.com References: <20230727212647.4182407-1-charlie@rivosinc.com> <20230727212647.4182407-2-charlie@rivosinc.com> From: Alexandre Ghiti In-Reply-To: <20230727212647.4182407-2-charlie@rivosinc.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-GND-Sasl: alex@ghiti.fr X-Rspamd-Queue-Id: 2E50FA000D X-Rspam-User: X-Rspamd-Server: rspam02 X-Stat-Signature: js95xaah9zfrepte6jk6gm5sfmtzegjt X-HE-Tag: 1691315637-542659 X-HE-Meta: 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 ZFqyBif4 ZBysKdqcYhNnoJEH0Y4MrwhjBracOcD6F3OWK8FSoMs+pmInseZG0AmL2yYb+IKD2iPkDKaIq6gbu7dE6AHZA9kExiEogpHstldWUkIYOHwHAd7E= X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On 27/07/2023 23:26, Charlie Jenkins wrote: > Make sv48 the default address space for mmap as some applications > currently depend on this assumption. A hint address passed to mmap will > cause the largest address space that fits entirely into the hint to be > used. If the hint is less than or equal to 1<<38, an sv39 address will > be used. An exception is that if the hint address is 0, then a sv48 > address will be used. After an address space is completely full, the next > smallest address space will be used. > > Signed-off-by: Charlie Jenkins > --- > arch/riscv/include/asm/elf.h | 2 +- > arch/riscv/include/asm/pgtable.h | 20 +++++++++++- > arch/riscv/include/asm/processor.h | 52 ++++++++++++++++++++++++++---- > 3 files changed, 66 insertions(+), 8 deletions(-) > > diff --git a/arch/riscv/include/asm/elf.h b/arch/riscv/include/asm/elf.h > index c24280774caf..5d3368d5585c 100644 > --- a/arch/riscv/include/asm/elf.h > +++ b/arch/riscv/include/asm/elf.h > @@ -49,7 +49,7 @@ extern bool compat_elf_check_arch(Elf32_Ehdr *hdr); > * the loader. We need to make sure that it is out of the way of the program > * that it will "exec", and that there is sufficient room for the brk. > */ > -#define ELF_ET_DYN_BASE ((TASK_SIZE / 3) * 2) > +#define ELF_ET_DYN_BASE ((DEFAULT_MAP_WINDOW / 3) * 2) > > #ifdef CONFIG_64BIT > #ifdef CONFIG_COMPAT > diff --git a/arch/riscv/include/asm/pgtable.h b/arch/riscv/include/asm/pgtable.h > index 75970ee2bda2..c76a1ef094a4 100644 > --- a/arch/riscv/include/asm/pgtable.h > +++ b/arch/riscv/include/asm/pgtable.h > @@ -63,8 +63,26 @@ > * position vmemmap directly below the VMALLOC region. > */ > #ifdef CONFIG_64BIT > +#define VA_BITS_SV39 39 > +#define VA_BITS_SV48 48 > +#define VA_BITS_SV57 57 > + > +#define VA_USER_SV39 (UL(1) << (VA_BITS_SV39 - 1)) > +#define VA_USER_SV48 (UL(1) << (VA_BITS_SV48 - 1)) > +#define VA_USER_SV57 (UL(1) << (VA_BITS_SV57 - 1)) > + > #define VA_BITS (pgtable_l5_enabled ? \ > - 57 : (pgtable_l4_enabled ? 48 : 39)) > + VA_BITS_SV57 : (pgtable_l4_enabled ? VA_BITS_SV48 : VA_BITS_SV39)) > + > +#ifdef CONFIG_COMPAT > +#define MMAP_VA_BITS_64 ((VA_BITS >= VA_BITS_SV48) ? VA_BITS_SV48 : VA_BITS) > +#define MMAP_MIN_VA_BITS_64 ((VA_BITS >= VA_BITS_SV39) ? VA_BITS_SV39 : VA_BITS) Here the condition is always true right? > +#define MMAP_VA_BITS (test_thread_flag(TIF_32BIT) ? 32 : MMAP_VA_BITS_64) > +#define MMAP_MIN_VA_BITS (test_thread_flag(TIF_32BIT) ? 32 : MMAP_MIN_VA_BITS_64) I think you should use is_compat_task() here instead of test_thread_flag(TIF_32BIT). And what about introducing VA_BITS_SV32 instead of hardcoding 32? > +#else > +#define MMAP_VA_BITS ((VA_BITS >= VA_BITS_SV48) ? VA_BITS_SV48 : VA_BITS) > +#define MMAP_MIN_VA_BITS ((VA_BITS >= VA_BITS_SV39) ? VA_BITS_SV39 : VA_BITS) Ditto here. > +#endif > #else > #define VA_BITS 32 > #endif > diff --git a/arch/riscv/include/asm/processor.h b/arch/riscv/include/asm/processor.h > index c950a8d9edef..e810244ea951 100644 > --- a/arch/riscv/include/asm/processor.h > +++ b/arch/riscv/include/asm/processor.h > @@ -13,19 +13,59 @@ > > #include > > +#ifdef CONFIG_64BIT > +#define DEFAULT_MAP_WINDOW (UL(1) << (MMAP_VA_BITS - 1)) > +#define STACK_TOP_MAX TASK_SIZE_64 > + > +#define arch_get_mmap_end(addr, len, flags) \ > +({ \ > + unsigned long mmap_end; \ > + typeof(addr) _addr = (addr); \ > + if ((_addr) == 0 || (IS_ENABLED(CONFIG_COMPAT) && test_thread_flag(TIF_32BIT))) \ > + mmap_end = DEFAULT_MAP_WINDOW; \ Wouldn't that prevent a sv57 system to allocate sv57 addresses when sv48 is full unless explicitly asked? > + else if ((_addr) >= VA_USER_SV57) \ > + mmap_end = STACK_TOP_MAX; \ > + else if ((((_addr) >= VA_USER_SV48)) && (VA_BITS >= VA_BITS_SV48)) \ > + mmap_end = VA_USER_SV48; \ > + else \ > + mmap_end = VA_USER_SV39; \ > + mmap_end; \ > +}) > + > +#define arch_get_mmap_base(addr, base) \ > +({ \ > + unsigned long mmap_base; \ > + typeof(addr) _addr = (addr); \ > + typeof(base) _base = (base); \ > + unsigned long rnd_gap = (_base) - DEFAULT_MAP_WINDOW; \ > + if ((_addr) == 0 || (IS_ENABLED(CONFIG_COMPAT) && test_thread_flag(TIF_32BIT))) \ > + mmap_base = (_base); \ > + else if (((_addr) >= VA_USER_SV57) && (VA_BITS >= VA_BITS_SV57)) \ > + mmap_base = VA_USER_SV57 + rnd_gap; \ Shouldn't it be mmap_base = VA_USER_SV57 - rnd_gap? > + else if ((((_addr) >= VA_USER_SV48)) && (VA_BITS >= VA_BITS_SV48)) \ > + mmap_base = VA_USER_SV48 + rnd_gap; \ > + else \ > + mmap_base = VA_USER_SV39 + rnd_gap; \ > + mmap_base; \ > +}) > + > +#else > +#define DEFAULT_MAP_WINDOW TASK_SIZE > +#define STACK_TOP_MAX TASK_SIZE > +#endif > +#define STACK_ALIGN 16 > + > +#define STACK_TOP DEFAULT_MAP_WINDOW > + > /* > * This decides where the kernel will search for a free chunk of vm > * space during mmap's. > */ > -#define TASK_UNMAPPED_BASE PAGE_ALIGN(TASK_SIZE / 3) > - > -#define STACK_TOP TASK_SIZE > #ifdef CONFIG_64BIT > -#define STACK_TOP_MAX TASK_SIZE_64 > +#define TASK_UNMAPPED_BASE PAGE_ALIGN((UL(1) << MMAP_MIN_VA_BITS) / 3) > #else > -#define STACK_TOP_MAX TASK_SIZE > +#define TASK_UNMAPPED_BASE PAGE_ALIGN(TASK_SIZE / 3) > #endif > -#define STACK_ALIGN 16 > > #ifndef __ASSEMBLY__ >