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-rw-r--r--src/liblzma/check/crc32_fast.c2
-rw-r--r--src/liblzma/check/crc64_fast.c2
-rw-r--r--src/liblzma/check/crc_clmul.c45
-rw-r--r--src/liblzma/check/crc_common.h52
4 files changed, 51 insertions, 50 deletions
diff --git a/src/liblzma/check/crc32_fast.c b/src/liblzma/check/crc32_fast.c
index add93d55..73659049 100644
--- a/src/liblzma/check/crc32_fast.c
+++ b/src/liblzma/check/crc32_fast.c
@@ -130,7 +130,7 @@ typedef uint32_t (*crc32_func_type)(
static crc32_func_type
crc32_resolve(void)
{
- return lzma_is_clmul_supported() ? &lzma_crc32_clmul : &crc32_generic;
+ return is_clmul_supported() ? &lzma_crc32_clmul : &crc32_generic;
}
#if defined(HAVE_FUNC_ATTRIBUTE_IFUNC) && defined(__clang__)
diff --git a/src/liblzma/check/crc64_fast.c b/src/liblzma/check/crc64_fast.c
index 8acdc713..4e6633db 100644
--- a/src/liblzma/check/crc64_fast.c
+++ b/src/liblzma/check/crc64_fast.c
@@ -94,7 +94,7 @@ typedef uint64_t (*crc64_func_type)(
static crc64_func_type
crc64_resolve(void)
{
- return lzma_is_clmul_supported() ? &lzma_crc64_clmul : &crc64_generic;
+ return is_clmul_supported() ? &lzma_crc64_clmul : &crc64_generic;
}
#if defined(HAVE_FUNC_ATTRIBUTE_IFUNC) && defined(__clang__)
diff --git a/src/liblzma/check/crc_clmul.c b/src/liblzma/check/crc_clmul.c
index 7110fd7e..640415e7 100644
--- a/src/liblzma/check/crc_clmul.c
+++ b/src/liblzma/check/crc_clmul.c
@@ -372,48 +372,3 @@ lzma_crc64_clmul(const uint8_t *buf, size_t size, uint64_t crc)
&& defined(_M_IX86)
# pragma optimize("", on)
#endif
-
-
-////////////////////////
-// Detect CPU support //
-////////////////////////
-
-extern bool
-lzma_is_clmul_supported(void)
-{
- int success = 1;
- uint32_t r[4]; // eax, ebx, ecx, edx
-
-#if defined(_MSC_VER)
- // This needs <intrin.h> with MSVC. ICC has it as a built-in
- // on all platforms.
- __cpuid(r, 1);
-#elif defined(HAVE_CPUID_H)
- // Compared to just using __asm__ to run CPUID, this also checks
- // that CPUID is supported and saves and restores ebx as that is
- // needed with GCC < 5 with position-independent code (PIC).
- success = __get_cpuid(1, &r[0], &r[1], &r[2], &r[3]);
-#else
- // Just a fallback that shouldn't be needed.
- __asm__("cpuid\n\t"
- : "=a"(r[0]), "=b"(r[1]), "=c"(r[2]), "=d"(r[3])
- : "a"(1), "c"(0));
-#endif
-
- // Returns true if these are supported:
- // CLMUL (bit 1 in ecx)
- // SSSE3 (bit 9 in ecx)
- // SSE4.1 (bit 19 in ecx)
- const uint32_t ecx_mask = (1 << 1) | (1 << 9) | (1 << 19);
- return success && (r[2] & ecx_mask) == ecx_mask;
-
- // Alternative methods that weren't used:
- // - ICC's _may_i_use_cpu_feature: the other methods should work too.
- // - GCC >= 6 / Clang / ICX __builtin_cpu_supports("pclmul")
- //
- // CPUID decding is needed with MSVC anyway and older GCC. This keeps
- // the feature checks in the build system simpler too. The nice thing
- // about __builtin_cpu_supports would be that it generates very short
- // code as is it only reads a variable set at startup but a few bytes
- // doesn't matter here.
-}
diff --git a/src/liblzma/check/crc_common.h b/src/liblzma/check/crc_common.h
index 51ddd9d5..1783b5e7 100644
--- a/src/liblzma/check/crc_common.h
+++ b/src/liblzma/check/crc_common.h
@@ -99,11 +99,57 @@
# elif defined(HAVE_CPUID_H)
# include <cpuid.h>
# endif
+
+// is_clmul_supported() must be inlined in this header file because the
+// ifunc resolver function may not support calling a function in another
+// translation unit. Depending on compiler-toolchain and flags, a call to
+// a function defined in another translation unit could result in a
+// reference to the PLT, which is unsafe to do in an ifunc resolver. The
+// ifunc resolver runs very early when loading a shared library, so the PLT
+// entries may not be setup at that time. Inlining this function duplicates
+// the function body in crc32_resolve() and crc64_resolve(), but this is
+// acceptable because the function results in very few instructions.
+static inline bool
+is_clmul_supported(void)
+{
+ int success = 1;
+ uint32_t r[4]; // eax, ebx, ecx, edx
+
+#if defined(_MSC_VER)
+ // This needs <intrin.h> with MSVC. ICC has it as a built-in
+ // on all platforms.
+ __cpuid(r, 1);
+#elif defined(HAVE_CPUID_H)
+ // Compared to just using __asm__ to run CPUID, this also checks
+ // that CPUID is supported and saves and restores ebx as that is
+ // needed with GCC < 5 with position-independent code (PIC).
+ success = __get_cpuid(1, &r[0], &r[1], &r[2], &r[3]);
+#else
+ // Just a fallback that shouldn't be needed.
+ __asm__("cpuid\n\t"
+ : "=a"(r[0]), "=b"(r[1]), "=c"(r[2]), "=d"(r[3])
+ : "a"(1), "c"(0));
#endif
-/// Detect at runtime if the CPU supports the x86 CLMUL instruction when
-/// both the generic and CLMUL implementations are built.
-extern bool lzma_is_clmul_supported(void);
+ // Returns true if these are supported:
+ // CLMUL (bit 1 in ecx)
+ // SSSE3 (bit 9 in ecx)
+ // SSE4.1 (bit 19 in ecx)
+ const uint32_t ecx_mask = (1 << 1) | (1 << 9) | (1 << 19);
+ return success && (r[2] & ecx_mask) == ecx_mask;
+
+ // Alternative methods that weren't used:
+ // - ICC's _may_i_use_cpu_feature: the other methods should work too.
+ // - GCC >= 6 / Clang / ICX __builtin_cpu_supports("pclmul")
+ //
+ // CPUID decding is needed with MSVC anyway and older GCC. This keeps
+ // the feature checks in the build system simpler too. The nice thing
+ // about __builtin_cpu_supports would be that it generates very short
+ // code as is it only reads a variable set at startup but a few bytes
+ // doesn't matter here.
+}
+
+#endif
/// CRC32 implemented with the x86 CLMUL instruction.
extern uint32_t lzma_crc32_clmul(const uint8_t *buf, size_t size,