[3/5] tunables: Use glibc.tune.hwcap_mask tunable instead of _dl_hwcap_mask
Commit Message
Drop _dl_hwcap_mask when building with tunables. This completes the
transition of hwcap_mask reading from _dl_hwcap_mask to tunables.
* elf/dl-cache.c: Include dl-tunables.h.
(_dl_load_cache_lookup)[HAVE_TUNABLES]: Read
glibc.tune.hwcap_mask.
* elf/dl-hwcaps.c: Include dl-tunables.h.
(_dl_important_hwcaps)[HAVE_TUNABLES]: Read and update
glibc.tune.hwcap_mask.
* sysdeps/sparc/sparc32/dl-machine.h: Likewise.
* elf/dl-support.c (_dl_hwcap2)[HAVE_TUNABLES]: Drop
_dl_hwcap_mask.
* elf/dl-tunables.c (__tunable_set_val): Make a hidden alias.
* elf/dl-tunables.h (__tunable_set_val): Likewise.
* elf/rtld.c (rtld_global_ro)[HAVE_TUNABLES]: Drop
_dl_hwcap_mask.
(process_envvars)[HAVE_TUNABLES]: Likewise.
* sysdeps/generic/ldsodefs.h (rtld_global_ro)[HAVE_TUNABLES]:
Likewise.
* sysdeps/x86/cpu-features.c (init_cpu_features): Don't
initialize dl_hwcap_mask when tunables are enabled.
---
elf/dl-cache.c | 9 ++++++++-
elf/dl-hwcaps.c | 15 +++++++++++++--
elf/dl-support.c | 2 ++
elf/dl-tunables.c | 1 +
elf/dl-tunables.h | 2 ++
elf/rtld.c | 4 ++++
sysdeps/generic/ldsodefs.h | 2 ++
sysdeps/sparc/sparc32/dl-machine.h | 8 +++++++-
sysdeps/x86/cpu-features.c | 4 ++++
9 files changed, 43 insertions(+), 4 deletions(-)
Comments
On 18/05/2017 17:07, Siddhesh Poyarekar wrote:
> Drop _dl_hwcap_mask when building with tunables. This completes the
> transition of hwcap_mask reading from _dl_hwcap_mask to tunables.
>
> * elf/dl-cache.c: Include dl-tunables.h.
> (_dl_load_cache_lookup)[HAVE_TUNABLES]: Read
> glibc.tune.hwcap_mask.
> * elf/dl-hwcaps.c: Include dl-tunables.h.
> (_dl_important_hwcaps)[HAVE_TUNABLES]: Read and update
> glibc.tune.hwcap_mask.
> * sysdeps/sparc/sparc32/dl-machine.h: Likewise.
> * elf/dl-support.c (_dl_hwcap2)[HAVE_TUNABLES]: Drop
> _dl_hwcap_mask.
> * elf/dl-tunables.c (__tunable_set_val): Make a hidden alias.
> * elf/dl-tunables.h (__tunable_set_val): Likewise.
> * elf/rtld.c (rtld_global_ro)[HAVE_TUNABLES]: Drop
> _dl_hwcap_mask.
> (process_envvars)[HAVE_TUNABLES]: Likewise.
> * sysdeps/generic/ldsodefs.h (rtld_global_ro)[HAVE_TUNABLES]:
> Likewise.
> * sysdeps/x86/cpu-features.c (init_cpu_features): Don't
> initialize dl_hwcap_mask when tunables are enabled.
LGTM.
> ---
> elf/dl-cache.c | 9 ++++++++-
> elf/dl-hwcaps.c | 15 +++++++++++++--
> elf/dl-support.c | 2 ++
> elf/dl-tunables.c | 1 +
> elf/dl-tunables.h | 2 ++
> elf/rtld.c | 4 ++++
> sysdeps/generic/ldsodefs.h | 2 ++
> sysdeps/sparc/sparc32/dl-machine.h | 8 +++++++-
> sysdeps/x86/cpu-features.c | 4 ++++
> 9 files changed, 43 insertions(+), 4 deletions(-)
>
> diff --git a/elf/dl-cache.c b/elf/dl-cache.c
> index 017c78a..b7ae05c 100644
> --- a/elf/dl-cache.c
> +++ b/elf/dl-cache.c
> @@ -24,6 +24,7 @@
> #include <dl-procinfo.h>
> #include <stdint.h>
> #include <_itoa.h>
> +#include <dl-tunables.h>
>
> #ifndef _DL_PLATFORMS_COUNT
> # define _DL_PLATFORMS_COUNT 0
> @@ -258,8 +259,14 @@ _dl_load_cache_lookup (const char *name)
> if (platform != (uint64_t) -1)
> platform = 1ULL << platform;
>
> +#if HAVE_TUNABLES
> + uint64_t hwcap_mask = TUNABLE_GET (glibc, tune, hwcap_mask, uint64_t);
> +#else
> + uint64_t hwcap_mask = GLRO(dl_hwcap_mask);
> +#endif
> +
> #define _DL_HWCAP_TLS_MASK (1LL << 63)
> - uint64_t hwcap_exclude = ~((GLRO(dl_hwcap) & GLRO(dl_hwcap_mask))
> + uint64_t hwcap_exclude = ~((GLRO(dl_hwcap) & hwcap_mask)
> | _DL_HWCAP_PLATFORM | _DL_HWCAP_TLS_MASK);
>
> /* Only accept hwcap if it's for the right platform. */
> diff --git a/elf/dl-hwcaps.c b/elf/dl-hwcaps.c
> index c437397..2b9f7f1 100644
> --- a/elf/dl-hwcaps.c
> +++ b/elf/dl-hwcaps.c
> @@ -24,6 +24,7 @@
> #include <ldsodefs.h>
>
> #include <dl-procinfo.h>
> +#include <dl-tunables.h>
>
> #ifdef _DL_FIRST_PLATFORM
> # define _DL_FIRST_EXTRA (_DL_FIRST_PLATFORM + _DL_PLATFORMS_COUNT)
> @@ -37,8 +38,13 @@ internal_function
> _dl_important_hwcaps (const char *platform, size_t platform_len, size_t *sz,
> size_t *max_capstrlen)
> {
> +#if HAVE_TUNABLES
> + uint64_t hwcap_mask = TUNABLE_GET (glibc, tune, hwcap_mask, uint64_t);
> +#else
> + uint64_t hwcap_mask = GLRO(dl_hwcap_mask);
> +#endif
> /* Determine how many important bits are set. */
> - uint64_t masked = GLRO(dl_hwcap) & GLRO(dl_hwcap_mask);
> + uint64_t masked = GLRO(dl_hwcap) & hwcap_mask;
> size_t cnt = platform != NULL;
> size_t n, m;
> size_t total;
> @@ -125,7 +131,12 @@ _dl_important_hwcaps (const char *platform, size_t platform_len, size_t *sz,
> LD_HWCAP_MASK environment variable (or default HWCAP_IMPORTANT).
> So there is no way to request ignoring an OS-supplied dsocap
> string and bit like you can ignore an OS-supplied HWCAP bit. */
> - GLRO(dl_hwcap_mask) |= (uint64_t) mask << _DL_FIRST_EXTRA;
> + hwcap_mask |= (uint64_t) mask << _DL_FIRST_EXTRA;
> +#if HAVE_TUNABLES
> + TUNABLE_UPDATE_VAL (glibc, tune, hwcap_mask, hwcap_mask, uint64_t);
> +#else
> + GLRO(dl_hwcap_mask) = hwcap_mask;
> +#endif
> size_t len;
> for (const char *p = dsocaps; p < dsocaps + dsocapslen; p += len + 1)
> {
> diff --git a/elf/dl-support.c b/elf/dl-support.c
> index 3c46a7a..c22be85 100644
> --- a/elf/dl-support.c
> +++ b/elf/dl-support.c
> @@ -164,6 +164,7 @@ uint64_t _dl_hwcap2 __attribute__ ((nocommon));
> /* The value of the FPU control word the kernel will preset in hardware. */
> fpu_control_t _dl_fpu_control = _FPU_DEFAULT;
>
> +#if !HAVE_TUNABLES
> /* This is not initialized to HWCAP_IMPORTANT, matching the definition
> of _dl_important_hwcaps, below, where no hwcap strings are ever
> used. This mask is still used to mediate the lookups in the cache
> @@ -171,6 +172,7 @@ fpu_control_t _dl_fpu_control = _FPU_DEFAULT;
> LD_HWCAP_MASK environment variable here), there is no real point in
> setting _dl_hwcap nonzero below, but we do anyway. */
> uint64_t _dl_hwcap_mask __attribute__ ((nocommon));
> +#endif
>
> /* Prevailing state of the stack. Generally this includes PF_X, indicating it's
> * executable but this isn't true for all platforms. */
> diff --git a/elf/dl-tunables.c b/elf/dl-tunables.c
> index abf10e5..be7733f 100644
> --- a/elf/dl-tunables.c
> +++ b/elf/dl-tunables.c
> @@ -497,3 +497,4 @@ cb:
> if (callback)
> callback (&cur->val);
> }
> +rtld_hidden_def (__tunable_set_val)
> diff --git a/elf/dl-tunables.h b/elf/dl-tunables.h
> index f465370..003e98b 100644
> --- a/elf/dl-tunables.h
> +++ b/elf/dl-tunables.h
> @@ -70,6 +70,8 @@ extern void __tunables_init (char **);
> extern void __tunable_set_val (tunable_id_t, void *, tunable_callback_t);
> extern void __tunable_update_val (tunable_id_t, void *);
>
> +rtld_hidden_proto (__tunable_set_val)
> +
> /* Get and return a tunable value. */
> # define TUNABLE_GET(__top, __ns, __id, __type) \
> ({ \
> diff --git a/elf/rtld.c b/elf/rtld.c
> index 319ef06..3746653 100644
> --- a/elf/rtld.c
> +++ b/elf/rtld.c
> @@ -159,7 +159,9 @@ struct rtld_global_ro _rtld_global_ro attribute_relro =
> ._dl_debug_fd = STDERR_FILENO,
> ._dl_use_load_bias = -2,
> ._dl_correct_cache_id = _DL_CACHE_DEFAULT_ID,
> +#if !HAVE_TUNABLES
> ._dl_hwcap_mask = HWCAP_IMPORTANT,
> +#endif
> ._dl_lazy = 1,
> ._dl_fpu_control = _FPU_DEFAULT,
> ._dl_pagesize = EXEC_PAGESIZE,
> @@ -2402,6 +2404,7 @@ process_envvars (enum mode *modep)
> _dl_show_auxv ();
> break;
>
> +#if !HAVE_TUNABLES
> case 10:
> /* Mask for the important hardware capabilities. */
> if (!__libc_enable_secure
> @@ -2409,6 +2412,7 @@ process_envvars (enum mode *modep)
> GLRO(dl_hwcap_mask) = __strtoul_internal (&envline[11], NULL,
> 0, 0);
> break;
> +#endif
>
> case 11:
> /* Path where the binary is found. */
> diff --git a/sysdeps/generic/ldsodefs.h b/sysdeps/generic/ldsodefs.h
> index f26a8b2..695ac24 100644
> --- a/sysdeps/generic/ldsodefs.h
> +++ b/sysdeps/generic/ldsodefs.h
> @@ -515,8 +515,10 @@ struct rtld_global_ro
> /* Mask for hardware capabilities that are available. */
> EXTERN uint64_t _dl_hwcap;
>
> +#if !HAVE_TUNABLES
> /* Mask for important hardware capabilities we honour. */
> EXTERN uint64_t _dl_hwcap_mask;
> +#endif
>
> #ifdef HAVE_AUX_VECTOR
> /* Pointer to the auxv list supplied to the program at startup. */
> diff --git a/sysdeps/sparc/sparc32/dl-machine.h b/sysdeps/sparc/sparc32/dl-machine.h
> index cf7272f..f5e8078 100644
> --- a/sysdeps/sparc/sparc32/dl-machine.h
> +++ b/sysdeps/sparc/sparc32/dl-machine.h
> @@ -27,6 +27,7 @@
> #include <sysdep.h>
> #include <tls.h>
> #include <dl-plt.h>
> +#include <elf/dl-tunables.h>
>
> /* Return nonzero iff ELF header is compatible with the running host. */
> static inline int
> @@ -39,7 +40,12 @@ elf_machine_matches_host (const Elf32_Ehdr *ehdr)
> /* XXX The following is wrong! Dave Miller rejected to implement it
> correctly. If this causes problems shoot *him*! */
> #ifdef SHARED
> - return GLRO(dl_hwcap) & GLRO(dl_hwcap_mask) & HWCAP_SPARC_V9;
> +# if HAVE_TUNABLES
> + uint64_t hwcap_mask = TUNABLE_GET (glibc, tune, hwcap_mask, uint64_t);
> +# else
> + uint64_t hwcap_mask = GLRO(dl_hwcap_mask);
> +# endif
> + return GLRO(dl_hwcap) & hwcap_mask & HWCAP_SPARC_V9;
> #else
> return GLRO(dl_hwcap) & HWCAP_SPARC_V9;
> #endif
> diff --git a/sysdeps/x86/cpu-features.c b/sysdeps/x86/cpu-features.c
> index b481f50..4fe58bf 100644
> --- a/sysdeps/x86/cpu-features.c
> +++ b/sysdeps/x86/cpu-features.c
> @@ -316,7 +316,11 @@ no_cpuid:
> /* Reuse dl_platform, dl_hwcap and dl_hwcap_mask for x86. */
> GLRO(dl_platform) = NULL;
> GLRO(dl_hwcap) = 0;
> +#if !HAVE_TUNABLES
> + /* The glibc.tune.hwcap_mask tunable is initialized already, so no need to do
> + this. */
> GLRO(dl_hwcap_mask) = HWCAP_IMPORTANT;
> +#endif
>
> # ifdef __x86_64__
> if (cpu_features->kind == arch_kind_intel)
>
@@ -24,6 +24,7 @@
#include <dl-procinfo.h>
#include <stdint.h>
#include <_itoa.h>
+#include <dl-tunables.h>
#ifndef _DL_PLATFORMS_COUNT
# define _DL_PLATFORMS_COUNT 0
@@ -258,8 +259,14 @@ _dl_load_cache_lookup (const char *name)
if (platform != (uint64_t) -1)
platform = 1ULL << platform;
+#if HAVE_TUNABLES
+ uint64_t hwcap_mask = TUNABLE_GET (glibc, tune, hwcap_mask, uint64_t);
+#else
+ uint64_t hwcap_mask = GLRO(dl_hwcap_mask);
+#endif
+
#define _DL_HWCAP_TLS_MASK (1LL << 63)
- uint64_t hwcap_exclude = ~((GLRO(dl_hwcap) & GLRO(dl_hwcap_mask))
+ uint64_t hwcap_exclude = ~((GLRO(dl_hwcap) & hwcap_mask)
| _DL_HWCAP_PLATFORM | _DL_HWCAP_TLS_MASK);
/* Only accept hwcap if it's for the right platform. */
@@ -24,6 +24,7 @@
#include <ldsodefs.h>
#include <dl-procinfo.h>
+#include <dl-tunables.h>
#ifdef _DL_FIRST_PLATFORM
# define _DL_FIRST_EXTRA (_DL_FIRST_PLATFORM + _DL_PLATFORMS_COUNT)
@@ -37,8 +38,13 @@ internal_function
_dl_important_hwcaps (const char *platform, size_t platform_len, size_t *sz,
size_t *max_capstrlen)
{
+#if HAVE_TUNABLES
+ uint64_t hwcap_mask = TUNABLE_GET (glibc, tune, hwcap_mask, uint64_t);
+#else
+ uint64_t hwcap_mask = GLRO(dl_hwcap_mask);
+#endif
/* Determine how many important bits are set. */
- uint64_t masked = GLRO(dl_hwcap) & GLRO(dl_hwcap_mask);
+ uint64_t masked = GLRO(dl_hwcap) & hwcap_mask;
size_t cnt = platform != NULL;
size_t n, m;
size_t total;
@@ -125,7 +131,12 @@ _dl_important_hwcaps (const char *platform, size_t platform_len, size_t *sz,
LD_HWCAP_MASK environment variable (or default HWCAP_IMPORTANT).
So there is no way to request ignoring an OS-supplied dsocap
string and bit like you can ignore an OS-supplied HWCAP bit. */
- GLRO(dl_hwcap_mask) |= (uint64_t) mask << _DL_FIRST_EXTRA;
+ hwcap_mask |= (uint64_t) mask << _DL_FIRST_EXTRA;
+#if HAVE_TUNABLES
+ TUNABLE_UPDATE_VAL (glibc, tune, hwcap_mask, hwcap_mask, uint64_t);
+#else
+ GLRO(dl_hwcap_mask) = hwcap_mask;
+#endif
size_t len;
for (const char *p = dsocaps; p < dsocaps + dsocapslen; p += len + 1)
{
@@ -164,6 +164,7 @@ uint64_t _dl_hwcap2 __attribute__ ((nocommon));
/* The value of the FPU control word the kernel will preset in hardware. */
fpu_control_t _dl_fpu_control = _FPU_DEFAULT;
+#if !HAVE_TUNABLES
/* This is not initialized to HWCAP_IMPORTANT, matching the definition
of _dl_important_hwcaps, below, where no hwcap strings are ever
used. This mask is still used to mediate the lookups in the cache
@@ -171,6 +172,7 @@ fpu_control_t _dl_fpu_control = _FPU_DEFAULT;
LD_HWCAP_MASK environment variable here), there is no real point in
setting _dl_hwcap nonzero below, but we do anyway. */
uint64_t _dl_hwcap_mask __attribute__ ((nocommon));
+#endif
/* Prevailing state of the stack. Generally this includes PF_X, indicating it's
* executable but this isn't true for all platforms. */
@@ -497,3 +497,4 @@ cb:
if (callback)
callback (&cur->val);
}
+rtld_hidden_def (__tunable_set_val)
@@ -70,6 +70,8 @@ extern void __tunables_init (char **);
extern void __tunable_set_val (tunable_id_t, void *, tunable_callback_t);
extern void __tunable_update_val (tunable_id_t, void *);
+rtld_hidden_proto (__tunable_set_val)
+
/* Get and return a tunable value. */
# define TUNABLE_GET(__top, __ns, __id, __type) \
({ \
@@ -159,7 +159,9 @@ struct rtld_global_ro _rtld_global_ro attribute_relro =
._dl_debug_fd = STDERR_FILENO,
._dl_use_load_bias = -2,
._dl_correct_cache_id = _DL_CACHE_DEFAULT_ID,
+#if !HAVE_TUNABLES
._dl_hwcap_mask = HWCAP_IMPORTANT,
+#endif
._dl_lazy = 1,
._dl_fpu_control = _FPU_DEFAULT,
._dl_pagesize = EXEC_PAGESIZE,
@@ -2402,6 +2404,7 @@ process_envvars (enum mode *modep)
_dl_show_auxv ();
break;
+#if !HAVE_TUNABLES
case 10:
/* Mask for the important hardware capabilities. */
if (!__libc_enable_secure
@@ -2409,6 +2412,7 @@ process_envvars (enum mode *modep)
GLRO(dl_hwcap_mask) = __strtoul_internal (&envline[11], NULL,
0, 0);
break;
+#endif
case 11:
/* Path where the binary is found. */
@@ -515,8 +515,10 @@ struct rtld_global_ro
/* Mask for hardware capabilities that are available. */
EXTERN uint64_t _dl_hwcap;
+#if !HAVE_TUNABLES
/* Mask for important hardware capabilities we honour. */
EXTERN uint64_t _dl_hwcap_mask;
+#endif
#ifdef HAVE_AUX_VECTOR
/* Pointer to the auxv list supplied to the program at startup. */
@@ -27,6 +27,7 @@
#include <sysdep.h>
#include <tls.h>
#include <dl-plt.h>
+#include <elf/dl-tunables.h>
/* Return nonzero iff ELF header is compatible with the running host. */
static inline int
@@ -39,7 +40,12 @@ elf_machine_matches_host (const Elf32_Ehdr *ehdr)
/* XXX The following is wrong! Dave Miller rejected to implement it
correctly. If this causes problems shoot *him*! */
#ifdef SHARED
- return GLRO(dl_hwcap) & GLRO(dl_hwcap_mask) & HWCAP_SPARC_V9;
+# if HAVE_TUNABLES
+ uint64_t hwcap_mask = TUNABLE_GET (glibc, tune, hwcap_mask, uint64_t);
+# else
+ uint64_t hwcap_mask = GLRO(dl_hwcap_mask);
+# endif
+ return GLRO(dl_hwcap) & hwcap_mask & HWCAP_SPARC_V9;
#else
return GLRO(dl_hwcap) & HWCAP_SPARC_V9;
#endif
@@ -316,7 +316,11 @@ no_cpuid:
/* Reuse dl_platform, dl_hwcap and dl_hwcap_mask for x86. */
GLRO(dl_platform) = NULL;
GLRO(dl_hwcap) = 0;
+#if !HAVE_TUNABLES
+ /* The glibc.tune.hwcap_mask tunable is initialized already, so no need to do
+ this. */
GLRO(dl_hwcap_mask) = HWCAP_IMPORTANT;
+#endif
# ifdef __x86_64__
if (cpu_features->kind == arch_kind_intel)