arm64/cpuinfo: Define HWCAP name arrays per their actual bit definitions

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.

Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
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
Link: https://lore.kernel.org/r/1599630535-29337-1-git-send-email-anshuman.khandual@arm.com
Signed-off-by: Will Deacon <will@kernel.org>

1 files changed, 92 insertions, 85 deletions

diff --git a/arch/arm64/kernel/cpuinfo.c b/arch/arm64/kernel/cpuinfo.c
index d0076c2159e6..25113245825c 100644
--- a/arch/arm64/kernel/cpuinfo.c
+++ b/arch/arm64/kernel/cpuinfo.c
@@ -43,94 +43,92 @@ 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",
-	/* reserved for "mte" */
-	NULL
+	[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",
 };
 
 #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",
 };
 #endif /* CONFIG_COMPAT */
 
@@ -166,16 +164,25 @@ 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++)
+			for (j = 0; j < ARRAY_SIZE(compat_hwcap2_str); j++)
 				if (compat_elf_hwcap2 & (1 << j))
 					seq_printf(m, " %s", compat_hwcap2_str[j]);
 #endif /* CONFIG_COMPAT */
 		} else {
-			for (j = 0; hwcap_str[j]; j++)
+			for (j = 0; j < ARRAY_SIZE(hwcap_str); j++)
 				if (cpu_have_feature(j))
 					seq_printf(m, " %s", hwcap_str[j]);
 		}