| Message ID | 1597665863-564-1-git-send-email-anshuman.khandual@arm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [V3] arm64/cpuinfo: Define HWCAP name arrays per their actual bit definitions | expand |
On Mon, Aug 17, 2020 at 05:34:23PM +0530, Anshuman Khandual wrote: > HWCAP name arrays (hwcap_str, compat_hwcap_str, compat_hwcap2_str) that are > scanned for /proc/cpuinfo are detached from their bit definitions making it > vulnerable and difficult to correlate. It is also bit problematic because > during /proc/cpuinfo dump these arrays get traversed sequentially assuming > they reflect and match actual HWCAP bit sequence, to test various features > for a given CPU. This redefines name arrays per their HWCAP bit definitions > . It also warns after detecting any feature which is not expected on arm64. > > Cc: Catalin Marinas <catalin.marinas@arm.com> > Cc: Will Deacon <will@kernel.org> > Cc: Mark Brown <broonie@kernel.org> > Cc: Dave Martin <Dave.Martin@arm.com> > Cc: Ard Biesheuvel <ardb@kernel.org> > Cc: Mark Rutland <mark.rutland@arm.com> > Cc: Suzuki K Poulose <suzuki.poulose@arm.com> > Cc: linux-arm-kernel@lists.infradead.org > Cc: linux-kernel@vger.kernel.org > Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com> > --- > This applies on 5.9-rc1 > > Mark, since the patch has changed I have dropped your Acked-by: tag. Are you > happy to give a new one ? > > Changes in V3: > > - Moved name arrays to (arch/arm64/kernel/cpuinfo.c) to prevent a build warning > - Replaced string values with NULL for all compat features not possible on arm64 > - Changed compat_hwcap_str[] iteration on size as some NULL values are expected > - Warn once after detecting any feature on arm64 that is not expected > > Changes in V2: (https://patchwork.kernel.org/patch/11533755/) > > - Defined COMPAT_KERNEL_HWCAP[2] and updated the name arrays per Mark > - Updated the commit message as required > > Changes in V1: (https://patchwork.kernel.org/patch/11532945/) > > arch/arm64/include/asm/hwcap.h | 9 +++ > arch/arm64/kernel/cpuinfo.c | 172 ++++++++++++++++++++++------------------- > 2 files changed, 100 insertions(+), 81 deletions(-) [...] > + [KERNEL_HWCAP_FP] = "fp", > + [KERNEL_HWCAP_ASIMD] = "asimd", > + [KERNEL_HWCAP_EVTSTRM] = "evtstrm", > + [KERNEL_HWCAP_AES] = "aes", It would be nice if the cap and the string were generated by the same macro, along the lines of: #define KERNEL_HWCAP(c) [KERNEL_HWCAP_##c] = #c, Does making the constants mixed case break anything, or is it just really churny to do? > @@ -166,9 +167,18 @@ static int c_show(struct seq_file *m, void *v) > seq_puts(m, "Features\t:"); > if (compat) { > #ifdef CONFIG_COMPAT > - for (j = 0; compat_hwcap_str[j]; j++) > - if (compat_elf_hwcap & (1 << j)) > + for (j = 0; j < ARRAY_SIZE(compat_hwcap_str); j++) { > + if (compat_elf_hwcap & (1 << j)) { > + /* > + * Warn once if any feature should not > + * have been present on arm64 platform. > + */ > + if (WARN_ON_ONCE(!compat_hwcap_str[j])) > + continue; > + > seq_printf(m, " %s", compat_hwcap_str[j]); > + } > + } > > for (j = 0; compat_hwcap2_str[j]; j++) Hmm, I find this pretty confusing now as compat_hwcap_str is not NULL terminated and must be traversed with a loop bounded by ARRAY_SIZE(...), whereas compat_hwcap2_str *is* NULL terminated and is traversed until you hit the sentinel. I think hwcap_str, compat_hwcap_str and compat_hwcap2_str should be identical in this regard. Will
On 09/07/2020 05:46 PM, Will Deacon wrote: > On Mon, Aug 17, 2020 at 05:34:23PM +0530, Anshuman Khandual wrote: >> HWCAP name arrays (hwcap_str, compat_hwcap_str, compat_hwcap2_str) that are >> scanned for /proc/cpuinfo are detached from their bit definitions making it >> vulnerable and difficult to correlate. It is also bit problematic because >> during /proc/cpuinfo dump these arrays get traversed sequentially assuming >> they reflect and match actual HWCAP bit sequence, to test various features >> for a given CPU. This redefines name arrays per their HWCAP bit definitions >> . It also warns after detecting any feature which is not expected on arm64. >> >> Cc: Catalin Marinas <catalin.marinas@arm.com> >> Cc: Will Deacon <will@kernel.org> >> Cc: Mark Brown <broonie@kernel.org> >> Cc: Dave Martin <Dave.Martin@arm.com> >> Cc: Ard Biesheuvel <ardb@kernel.org> >> Cc: Mark Rutland <mark.rutland@arm.com> >> Cc: Suzuki K Poulose <suzuki.poulose@arm.com> >> Cc: linux-arm-kernel@lists.infradead.org >> Cc: linux-kernel@vger.kernel.org >> Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com> >> --- >> This applies on 5.9-rc1 >> >> Mark, since the patch has changed I have dropped your Acked-by: tag. Are you >> happy to give a new one ? >> >> Changes in V3: >> >> - Moved name arrays to (arch/arm64/kernel/cpuinfo.c) to prevent a build warning >> - Replaced string values with NULL for all compat features not possible on arm64 >> - Changed compat_hwcap_str[] iteration on size as some NULL values are expected >> - Warn once after detecting any feature on arm64 that is not expected >> >> Changes in V2: (https://patchwork.kernel.org/patch/11533755/) >> >> - Defined COMPAT_KERNEL_HWCAP[2] and updated the name arrays per Mark >> - Updated the commit message as required >> >> Changes in V1: (https://patchwork.kernel.org/patch/11532945/) >> >> arch/arm64/include/asm/hwcap.h | 9 +++ >> arch/arm64/kernel/cpuinfo.c | 172 ++++++++++++++++++++++------------------- >> 2 files changed, 100 insertions(+), 81 deletions(-) > > [...] > >> + [KERNEL_HWCAP_FP] = "fp", >> + [KERNEL_HWCAP_ASIMD] = "asimd", >> + [KERNEL_HWCAP_EVTSTRM] = "evtstrm", >> + [KERNEL_HWCAP_AES] = "aes", > > It would be nice if the cap and the string were generated by the same > macro, along the lines of: > > #define KERNEL_HWCAP(c) [KERNEL_HWCAP_##c] = #c, > > Does making the constants mixed case break anything, or is it just really > churny to do? Currently all existing HWCAP feature strings are lower case, above change will make them into upper case instead. I could not find a method to force convert #c into lower case constant strings in the macro definition. Would not changing the HWCAP string case here, break user interface ? > >> @@ -166,9 +167,18 @@ static int c_show(struct seq_file *m, void *v) >> seq_puts(m, "Features\t:"); >> if (compat) { >> #ifdef CONFIG_COMPAT >> - for (j = 0; compat_hwcap_str[j]; j++) >> - if (compat_elf_hwcap & (1 << j)) >> + for (j = 0; j < ARRAY_SIZE(compat_hwcap_str); j++) { >> + if (compat_elf_hwcap & (1 << j)) { >> + /* >> + * Warn once if any feature should not >> + * have been present on arm64 platform. >> + */ >> + if (WARN_ON_ONCE(!compat_hwcap_str[j])) >> + continue; >> + >> seq_printf(m, " %s", compat_hwcap_str[j]); >> + } >> + } >> >> for (j = 0; compat_hwcap2_str[j]; j++) > > Hmm, I find this pretty confusing now as compat_hwcap_str is not NULL > terminated and must be traversed with a loop bounded by ARRAY_SIZE(...), Right. Thats because unlike before, it can now have some intermediate NULL entries. Hence NULL sentinel based traversal wont be possible any more. > whereas compat_hwcap2_str *is* NULL terminated and is traversed until you > hit the sentinel. > > I think hwcap_str, compat_hwcap_str and compat_hwcap2_str should be > identical in this regard. Sure, will make the traversal based on ARRAY_SIZE() for all three arrays here, to make that uniform. > > Will >
On Tue, Sep 08, 2020 at 10:43:12AM +0530, Anshuman Khandual wrote: > > > On 09/07/2020 05:46 PM, Will Deacon wrote: > > On Mon, Aug 17, 2020 at 05:34:23PM +0530, Anshuman Khandual wrote: > >> HWCAP name arrays (hwcap_str, compat_hwcap_str, compat_hwcap2_str) that are > >> scanned for /proc/cpuinfo are detached from their bit definitions making it > >> vulnerable and difficult to correlate. It is also bit problematic because > >> during /proc/cpuinfo dump these arrays get traversed sequentially assuming > >> they reflect and match actual HWCAP bit sequence, to test various features > >> for a given CPU. This redefines name arrays per their HWCAP bit definitions > >> . It also warns after detecting any feature which is not expected on arm64. > >> > >> Cc: Catalin Marinas <catalin.marinas@arm.com> > >> Cc: Will Deacon <will@kernel.org> > >> Cc: Mark Brown <broonie@kernel.org> > >> Cc: Dave Martin <Dave.Martin@arm.com> > >> Cc: Ard Biesheuvel <ardb@kernel.org> > >> Cc: Mark Rutland <mark.rutland@arm.com> > >> Cc: Suzuki K Poulose <suzuki.poulose@arm.com> > >> Cc: linux-arm-kernel@lists.infradead.org > >> Cc: linux-kernel@vger.kernel.org > >> Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com> > >> --- > >> This applies on 5.9-rc1 > >> > >> Mark, since the patch has changed I have dropped your Acked-by: tag. Are you > >> happy to give a new one ? > >> > >> Changes in V3: > >> > >> - Moved name arrays to (arch/arm64/kernel/cpuinfo.c) to prevent a build warning > >> - Replaced string values with NULL for all compat features not possible on arm64 > >> - Changed compat_hwcap_str[] iteration on size as some NULL values are expected > >> - Warn once after detecting any feature on arm64 that is not expected > >> > >> Changes in V2: (https://patchwork.kernel.org/patch/11533755/) > >> > >> - Defined COMPAT_KERNEL_HWCAP[2] and updated the name arrays per Mark > >> - Updated the commit message as required > >> > >> Changes in V1: (https://patchwork.kernel.org/patch/11532945/) > >> > >> arch/arm64/include/asm/hwcap.h | 9 +++ > >> arch/arm64/kernel/cpuinfo.c | 172 ++++++++++++++++++++++------------------- > >> 2 files changed, 100 insertions(+), 81 deletions(-) > > > > [...] > > > >> + [KERNEL_HWCAP_FP] = "fp", > >> + [KERNEL_HWCAP_ASIMD] = "asimd", > >> + [KERNEL_HWCAP_EVTSTRM] = "evtstrm", > >> + [KERNEL_HWCAP_AES] = "aes", > > > > It would be nice if the cap and the string were generated by the same > > macro, along the lines of: > > > > #define KERNEL_HWCAP(c) [KERNEL_HWCAP_##c] = #c, > > > > Does making the constants mixed case break anything, or is it just really > > churny to do? > > Currently all existing HWCAP feature strings are lower case, above change > will make them into upper case instead. I could not find a method to force > convert #c into lower case constant strings in the macro definition. Would > not changing the HWCAP string case here, break user interface ? Yes, we can't change the user-visible strings, but what's wrong with having e.g. KERNEL_HWCAP_fp instead of KERNEL_HWCAP_FP? Will
On 09/08/2020 01:11 PM, Will Deacon wrote: > On Tue, Sep 08, 2020 at 10:43:12AM +0530, Anshuman Khandual wrote: >> >> >> On 09/07/2020 05:46 PM, Will Deacon wrote: >>> On Mon, Aug 17, 2020 at 05:34:23PM +0530, Anshuman Khandual wrote: >>>> HWCAP name arrays (hwcap_str, compat_hwcap_str, compat_hwcap2_str) that are >>>> scanned for /proc/cpuinfo are detached from their bit definitions making it >>>> vulnerable and difficult to correlate. It is also bit problematic because >>>> during /proc/cpuinfo dump these arrays get traversed sequentially assuming >>>> they reflect and match actual HWCAP bit sequence, to test various features >>>> for a given CPU. This redefines name arrays per their HWCAP bit definitions >>>> . It also warns after detecting any feature which is not expected on arm64. >>>> >>>> Cc: Catalin Marinas <catalin.marinas@arm.com> >>>> Cc: Will Deacon <will@kernel.org> >>>> Cc: Mark Brown <broonie@kernel.org> >>>> Cc: Dave Martin <Dave.Martin@arm.com> >>>> Cc: Ard Biesheuvel <ardb@kernel.org> >>>> Cc: Mark Rutland <mark.rutland@arm.com> >>>> Cc: Suzuki K Poulose <suzuki.poulose@arm.com> >>>> Cc: linux-arm-kernel@lists.infradead.org >>>> Cc: linux-kernel@vger.kernel.org >>>> Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com> >>>> --- >>>> This applies on 5.9-rc1 >>>> >>>> Mark, since the patch has changed I have dropped your Acked-by: tag. Are you >>>> happy to give a new one ? >>>> >>>> Changes in V3: >>>> >>>> - Moved name arrays to (arch/arm64/kernel/cpuinfo.c) to prevent a build warning >>>> - Replaced string values with NULL for all compat features not possible on arm64 >>>> - Changed compat_hwcap_str[] iteration on size as some NULL values are expected >>>> - Warn once after detecting any feature on arm64 that is not expected >>>> >>>> Changes in V2: (https://patchwork.kernel.org/patch/11533755/) >>>> >>>> - Defined COMPAT_KERNEL_HWCAP[2] and updated the name arrays per Mark >>>> - Updated the commit message as required >>>> >>>> Changes in V1: (https://patchwork.kernel.org/patch/11532945/) >>>> >>>> arch/arm64/include/asm/hwcap.h | 9 +++ >>>> arch/arm64/kernel/cpuinfo.c | 172 ++++++++++++++++++++++------------------- >>>> 2 files changed, 100 insertions(+), 81 deletions(-) >>> >>> [...] >>> >>>> + [KERNEL_HWCAP_FP] = "fp", >>>> + [KERNEL_HWCAP_ASIMD] = "asimd", >>>> + [KERNEL_HWCAP_EVTSTRM] = "evtstrm", >>>> + [KERNEL_HWCAP_AES] = "aes", >>> >>> It would be nice if the cap and the string were generated by the same >>> macro, along the lines of: >>> >>> #define KERNEL_HWCAP(c) [KERNEL_HWCAP_##c] = #c, >>> >>> Does making the constants mixed case break anything, or is it just really >>> churny to do? >> >> Currently all existing HWCAP feature strings are lower case, above change >> will make them into upper case instead. I could not find a method to force >> convert #c into lower case constant strings in the macro definition. Would >> not changing the HWCAP string case here, break user interface ? > > Yes, we can't change the user-visible strings, but what's wrong with > having e.g. KERNEL_HWCAP_fp instead of KERNEL_HWCAP_FP? Unlike the new compat macros i.e COMPAT_KERNEL_HWCAP[2] in this patch, KERNEL_HWCAP_XXX macros are already defined and are getting used else where (arch/arm64/kernel/cpufeature.c) as well. [KERNEL_HWCAP_##c] can only be used here, if the input string is in upper case. Otherwise all these existing macros need to be changed first, which will result in too much code churn.
diff --git a/arch/arm64/include/asm/hwcap.h b/arch/arm64/include/asm/hwcap.h index 22f73fe..6493a4c 100644 --- a/arch/arm64/include/asm/hwcap.h +++ b/arch/arm64/include/asm/hwcap.h @@ -8,18 +8,27 @@ #include <uapi/asm/hwcap.h> #include <asm/cpufeature.h> +#define COMPAT_HWCAP_SWP (1 << 0) #define COMPAT_HWCAP_HALF (1 << 1) #define COMPAT_HWCAP_THUMB (1 << 2) +#define COMPAT_HWCAP_26BIT (1 << 3) #define COMPAT_HWCAP_FAST_MULT (1 << 4) +#define COMPAT_HWCAP_FPA (1 << 5) #define COMPAT_HWCAP_VFP (1 << 6) #define COMPAT_HWCAP_EDSP (1 << 7) +#define COMPAT_HWCAP_JAVA (1 << 8) +#define COMPAT_HWCAP_IWMMXT (1 << 9) +#define COMPAT_HWCAP_CRUNCH (1 << 10) +#define COMPAT_HWCAP_THUMBEE (1 << 11) #define COMPAT_HWCAP_NEON (1 << 12) #define COMPAT_HWCAP_VFPv3 (1 << 13) +#define COMPAT_HWCAP_VFPV3D16 (1 << 14) #define COMPAT_HWCAP_TLS (1 << 15) #define COMPAT_HWCAP_VFPv4 (1 << 16) #define COMPAT_HWCAP_IDIVA (1 << 17) #define COMPAT_HWCAP_IDIVT (1 << 18) #define COMPAT_HWCAP_IDIV (COMPAT_HWCAP_IDIVA|COMPAT_HWCAP_IDIVT) +#define COMPAT_HWCAP_VFPD32 (1 << 19) #define COMPAT_HWCAP_LPAE (1 << 20) #define COMPAT_HWCAP_EVTSTRM (1 << 21) diff --git a/arch/arm64/kernel/cpuinfo.c b/arch/arm64/kernel/cpuinfo.c index 393c6fb..382cb4c 100644 --- a/arch/arm64/kernel/cpuinfo.c +++ b/arch/arm64/kernel/cpuinfo.c @@ -43,94 +43,95 @@ static const char *icache_policy_str[] = { unsigned long __icache_flags; static const char *const hwcap_str[] = { - "fp", - "asimd", - "evtstrm", - "aes", - "pmull", - "sha1", - "sha2", - "crc32", - "atomics", - "fphp", - "asimdhp", - "cpuid", - "asimdrdm", - "jscvt", - "fcma", - "lrcpc", - "dcpop", - "sha3", - "sm3", - "sm4", - "asimddp", - "sha512", - "sve", - "asimdfhm", - "dit", - "uscat", - "ilrcpc", - "flagm", - "ssbs", - "sb", - "paca", - "pacg", - "dcpodp", - "sve2", - "sveaes", - "svepmull", - "svebitperm", - "svesha3", - "svesm4", - "flagm2", - "frint", - "svei8mm", - "svef32mm", - "svef64mm", - "svebf16", - "i8mm", - "bf16", - "dgh", - "rng", - "bti", + [KERNEL_HWCAP_FP] = "fp", + [KERNEL_HWCAP_ASIMD] = "asimd", + [KERNEL_HWCAP_EVTSTRM] = "evtstrm", + [KERNEL_HWCAP_AES] = "aes", + [KERNEL_HWCAP_PMULL] = "pmull", + [KERNEL_HWCAP_SHA1] = "sha1", + [KERNEL_HWCAP_SHA2] = "sha2", + [KERNEL_HWCAP_CRC32] = "crc32", + [KERNEL_HWCAP_ATOMICS] = "atomics", + [KERNEL_HWCAP_FPHP] = "fphp", + [KERNEL_HWCAP_ASIMDHP] = "asimdhp", + [KERNEL_HWCAP_CPUID] = "cpuid", + [KERNEL_HWCAP_ASIMDRDM] = "asimdrdm", + [KERNEL_HWCAP_JSCVT] = "jscvt", + [KERNEL_HWCAP_FCMA] = "fcma", + [KERNEL_HWCAP_LRCPC] = "lrcpc", + [KERNEL_HWCAP_DCPOP] = "dcpop", + [KERNEL_HWCAP_SHA3] = "sha3", + [KERNEL_HWCAP_SM3] = "sm3", + [KERNEL_HWCAP_SM4] = "sm4", + [KERNEL_HWCAP_ASIMDDP] = "asimddp", + [KERNEL_HWCAP_SHA512] = "sha512", + [KERNEL_HWCAP_SVE] = "sve", + [KERNEL_HWCAP_ASIMDFHM] = "asimdfhm", + [KERNEL_HWCAP_DIT] = "dit", + [KERNEL_HWCAP_USCAT] = "uscat", + [KERNEL_HWCAP_ILRCPC] = "ilrcpc", + [KERNEL_HWCAP_FLAGM] = "flagm", + [KERNEL_HWCAP_SSBS] = "ssbs", + [KERNEL_HWCAP_SB] = "sb", + [KERNEL_HWCAP_PACA] = "paca", + [KERNEL_HWCAP_PACG] = "pacg", + [KERNEL_HWCAP_DCPODP] = "dcpodp", + [KERNEL_HWCAP_SVE2] = "sve2", + [KERNEL_HWCAP_SVEAES] = "sveaes", + [KERNEL_HWCAP_SVEPMULL] = "svepmull", + [KERNEL_HWCAP_SVEBITPERM] = "svebitperm", + [KERNEL_HWCAP_SVESHA3] = "svesha3", + [KERNEL_HWCAP_SVESM4] = "svesm4", + [KERNEL_HWCAP_FLAGM2] = "flagm2", + [KERNEL_HWCAP_FRINT] = "frint", + [KERNEL_HWCAP_SVEI8MM] = "svei8mm", + [KERNEL_HWCAP_SVEF32MM] = "svef32mm", + [KERNEL_HWCAP_SVEF64MM] = "svef64mm", + [KERNEL_HWCAP_SVEBF16] = "svebf16", + [KERNEL_HWCAP_I8MM] = "i8mm", + [KERNEL_HWCAP_BF16] = "bf16", + [KERNEL_HWCAP_DGH] = "dgh", + [KERNEL_HWCAP_RNG] = "rng", + [KERNEL_HWCAP_BTI] = "bti", /* reserved for "mte" */ NULL }; #ifdef CONFIG_COMPAT +#define COMPAT_KERNEL_HWCAP(x) const_ilog2(COMPAT_HWCAP_ ## x) static const char *const compat_hwcap_str[] = { - "swp", - "half", - "thumb", - "26bit", - "fastmult", - "fpa", - "vfp", - "edsp", - "java", - "iwmmxt", - "crunch", - "thumbee", - "neon", - "vfpv3", - "vfpv3d16", - "tls", - "vfpv4", - "idiva", - "idivt", - "vfpd32", - "lpae", - "evtstrm", - NULL + [COMPAT_KERNEL_HWCAP(SWP)] = "swp", + [COMPAT_KERNEL_HWCAP(HALF)] = "half", + [COMPAT_KERNEL_HWCAP(THUMB)] = "thumb", + [COMPAT_KERNEL_HWCAP(26BIT)] = NULL, /* Not possible on arm64 */ + [COMPAT_KERNEL_HWCAP(FAST_MULT)] = "fastmult", + [COMPAT_KERNEL_HWCAP(FPA)] = NULL, /* Not possible on arm64 */ + [COMPAT_KERNEL_HWCAP(VFP)] = "vfp", + [COMPAT_KERNEL_HWCAP(EDSP)] = "edsp", + [COMPAT_KERNEL_HWCAP(JAVA)] = NULL, /* Not possible on arm64 */ + [COMPAT_KERNEL_HWCAP(IWMMXT)] = NULL, /* Not possible on arm64 */ + [COMPAT_KERNEL_HWCAP(CRUNCH)] = NULL, /* Not possible on arm64 */ + [COMPAT_KERNEL_HWCAP(THUMBEE)] = NULL, /* Not possible on arm64 */ + [COMPAT_KERNEL_HWCAP(NEON)] = "neon", + [COMPAT_KERNEL_HWCAP(VFPv3)] = "vfpv3", + [COMPAT_KERNEL_HWCAP(VFPV3D16)] = NULL, /* Not possible on arm64 */ + [COMPAT_KERNEL_HWCAP(TLS)] = "tls", + [COMPAT_KERNEL_HWCAP(VFPv4)] = "vfpv4", + [COMPAT_KERNEL_HWCAP(IDIVA)] = "idiva", + [COMPAT_KERNEL_HWCAP(IDIVT)] = "idivt", + [COMPAT_KERNEL_HWCAP(VFPD32)] = NULL, /* Not possible on arm64 */ + [COMPAT_KERNEL_HWCAP(LPAE)] = "lpae", + [COMPAT_KERNEL_HWCAP(EVTSTRM)] = "evtstrm", }; +#define COMPAT_KERNEL_HWCAP2(x) const_ilog2(COMPAT_HWCAP2_ ## x) static const char *const compat_hwcap2_str[] = { - "aes", - "pmull", - "sha1", - "sha2", - "crc32", - NULL + [COMPAT_KERNEL_HWCAP2(AES)] = "aes", + [COMPAT_KERNEL_HWCAP2(PMULL)] = "pmull", + [COMPAT_KERNEL_HWCAP2(SHA1)] = "sha1", + [COMPAT_KERNEL_HWCAP2(SHA2)] = "sha2", + [COMPAT_KERNEL_HWCAP2(CRC32)] = "crc32", + NULL, }; #endif /* CONFIG_COMPAT */ @@ -166,9 +167,18 @@ static int c_show(struct seq_file *m, void *v) seq_puts(m, "Features\t:"); if (compat) { #ifdef CONFIG_COMPAT - for (j = 0; compat_hwcap_str[j]; j++) - if (compat_elf_hwcap & (1 << j)) + for (j = 0; j < ARRAY_SIZE(compat_hwcap_str); j++) { + if (compat_elf_hwcap & (1 << j)) { + /* + * Warn once if any feature should not + * have been present on arm64 platform. + */ + if (WARN_ON_ONCE(!compat_hwcap_str[j])) + continue; + seq_printf(m, " %s", compat_hwcap_str[j]); + } + } for (j = 0; compat_hwcap2_str[j]; j++) if (compat_elf_hwcap2 & (1 << j))
HWCAP name arrays (hwcap_str, compat_hwcap_str, compat_hwcap2_str) that are scanned for /proc/cpuinfo are detached from their bit definitions making it vulnerable and difficult to correlate. It is also bit problematic because during /proc/cpuinfo dump these arrays get traversed sequentially assuming they reflect and match actual HWCAP bit sequence, to test various features for a given CPU. This redefines name arrays per their HWCAP bit definitions . It also warns after detecting any feature which is not expected on arm64. Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Will Deacon <will@kernel.org> Cc: Mark Brown <broonie@kernel.org> Cc: Dave Martin <Dave.Martin@arm.com> Cc: Ard Biesheuvel <ardb@kernel.org> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Suzuki K Poulose <suzuki.poulose@arm.com> Cc: linux-arm-kernel@lists.infradead.org Cc: linux-kernel@vger.kernel.org Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com> --- This applies on 5.9-rc1 Mark, since the patch has changed I have dropped your Acked-by: tag. Are you happy to give a new one ? Changes in V3: - Moved name arrays to (arch/arm64/kernel/cpuinfo.c) to prevent a build warning - Replaced string values with NULL for all compat features not possible on arm64 - Changed compat_hwcap_str[] iteration on size as some NULL values are expected - Warn once after detecting any feature on arm64 that is not expected Changes in V2: (https://patchwork.kernel.org/patch/11533755/) - Defined COMPAT_KERNEL_HWCAP[2] and updated the name arrays per Mark - Updated the commit message as required Changes in V1: (https://patchwork.kernel.org/patch/11532945/) arch/arm64/include/asm/hwcap.h | 9 +++ arch/arm64/kernel/cpuinfo.c | 172 ++++++++++++++++++++++------------------- 2 files changed, 100 insertions(+), 81 deletions(-)