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| author | Fenghua Yu | 2014-05-29 20:12:43 +0200 |
|---|---|---|
| committer | H. Peter Anvin | 2014-05-29 23:33:07 +0200 |
| commit | 7e7ce87f6ad4e1730364e5e76628b43c5759b700 (patch) | |
| tree | d22269d21df21bf4f10f8e7f03ffcc3ecc87be3b /arch/x86/kernel/xsave.c | |
| parent | x86/xsaves: Call booting time xsaves and xrstors in setup_init_fpu_buf (diff) | |
| download | kernel-qcow2-linux-7e7ce87f6ad4e1730364e5e76628b43c5759b700.tar.gz kernel-qcow2-linux-7e7ce87f6ad4e1730364e5e76628b43c5759b700.tar.xz kernel-qcow2-linux-7e7ce87f6ad4e1730364e5e76628b43c5759b700.zip | |
x86/xsaves: Enable xsaves/xrstors
If xsaves/xrstors is enabled, compacted format of xsave area will be used
and less memory may be used for context per process. And modified
optimization implemented in xsaves/xrstors improves performance of saving
xstate.
Signed-off-by: Fenghua Yu <fenghua.yu@intel.com>
Link: http://lkml.kernel.org/r/1401387164-43416-16-git-send-email-fenghua.yu@intel.com
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Diffstat (limited to 'arch/x86/kernel/xsave.c')
| -rw-r--r-- | arch/x86/kernel/xsave.c | 39 |
1 files changed, 33 insertions, 6 deletions
diff --git a/arch/x86/kernel/xsave.c b/arch/x86/kernel/xsave.c index 8fa7c7d4183d..f930f8ab92d1 100644 --- a/arch/x86/kernel/xsave.c +++ b/arch/x86/kernel/xsave.c @@ -8,6 +8,7 @@ #include <linux/bootmem.h> #include <linux/compat.h> +#include <linux/cpu.h> #include <asm/i387.h> #include <asm/fpu-internal.h> #include <asm/sigframe.h> @@ -24,7 +25,9 @@ u64 pcntxt_mask; struct xsave_struct *init_xstate_buf; static struct _fpx_sw_bytes fx_sw_reserved, fx_sw_reserved_ia32; -static unsigned int *xstate_offsets, *xstate_sizes, xstate_features; +static unsigned int *xstate_offsets, *xstate_sizes; +static unsigned int *xstate_comp_offsets, *xstate_comp_sizes; +static unsigned int xstate_features; /* * If a processor implementation discern that a processor state component is @@ -283,7 +286,7 @@ sanitize_restored_xstate(struct task_struct *tsk, if (use_xsave()) { /* These bits must be zero. */ - xsave_hdr->reserved1[0] = xsave_hdr->reserved1[1] = 0; + memset(xsave_hdr->reserved, 0, 48); /* * Init the state that is not present in the memory @@ -526,6 +529,30 @@ static int __init eager_fpu_setup(char *s) } __setup("eagerfpu=", eager_fpu_setup); + +/* + * Calculate total size of enabled xstates in XCR0/pcntxt_mask. + */ +static void __init init_xstate_size(void) +{ + unsigned int eax, ebx, ecx, edx; + int i; + + if (!cpu_has_xsaves) { + cpuid_count(XSTATE_CPUID, 0, &eax, &ebx, &ecx, &edx); + xstate_size = ebx; + return; + } + + xstate_size = FXSAVE_SIZE + XSAVE_HDR_SIZE; + for (i = 2; i < 64; i++) { + if (test_bit(i, (unsigned long *)&pcntxt_mask)) { + cpuid_count(XSTATE_CPUID, i, &eax, &ebx, &ecx, &edx); + xstate_size += eax; + } + } +} + /* * Enable and initialize the xsave feature. */ @@ -557,8 +584,7 @@ static void __init xstate_enable_boot_cpu(void) /* * Recompute the context size for enabled features */ - cpuid_count(XSTATE_CPUID, 0, &eax, &ebx, &ecx, &edx); - xstate_size = ebx; + init_xstate_size(); update_regset_xstate_info(xstate_size, pcntxt_mask); prepare_fx_sw_frame(); @@ -578,8 +604,9 @@ static void __init xstate_enable_boot_cpu(void) } } - pr_info("enabled xstate_bv 0x%llx, cntxt size 0x%x\n", - pcntxt_mask, xstate_size); + pr_info("enabled xstate_bv 0x%llx, cntxt size 0x%x using %s\n", + pcntxt_mask, xstate_size, + cpu_has_xsaves ? "compacted form" : "standard form"); } /* |