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authoryu-cheng yu <yu-cheng.yu@intel.com>2016-01-06 23:24:51 +0100
committerIngo Molnar <mingo@kernel.org>2016-01-12 11:51:20 +0100
commit4f81cbafcce2c603db7865e9d0e461f7947d77d4 (patch)
tree24f2f8e575902dd525c2eb89d6c086ab3cf6b655 /arch/x86/kernel/fpu
parentx86/mm: Use PAGE_ALIGNED instead of IS_ALIGNED (diff)
downloadlinux-4f81cbafcce2c603db7865e9d0e461f7947d77d4.tar.xz
linux-4f81cbafcce2c603db7865e9d0e461f7947d77d4.zip
x86/fpu: Fix early FPU command-line parsing
The function fpu__init_system() is executed before parse_early_param(). This causes wrong FPU configuration. This patch fixes this issue by parsing boot_command_line in the beginning of fpu__init_system(). With all four patches in this series, each parameter disables features as the following: eagerfpu=off: eagerfpu, avx, avx2, avx512, mpx no387: fpu nofxsr: fxsr, fxsropt, xmm noxsave: xsave, xsaveopt, xsaves, xsavec, avx, avx2, avx512, mpx, xgetbv1 noxsaveopt: xsaveopt noxsaves: xsaves Signed-off-by: Yu-cheng Yu <yu-cheng.yu@intel.com> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Borislav Petkov <bp@alien8.de> Cc: Borislav Petkov <bp@suse.de> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Fenghua Yu <fenghua.yu@intel.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Quentin Casasnovas <quentin.casasnovas@oracle.com> Cc: Ravi V. Shankar <ravi.v.shankar@intel.com> Cc: Sai Praneeth Prakhya <sai.praneeth.prakhya@intel.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: yu-cheng yu <yu-cheng.yu@intel.com> Link: http://lkml.kernel.org/r/1452119094-7252-2-git-send-email-yu-cheng.yu@intel.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'arch/x86/kernel/fpu')
-rw-r--r--arch/x86/kernel/fpu/init.c109
1 files changed, 38 insertions, 71 deletions
diff --git a/arch/x86/kernel/fpu/init.c b/arch/x86/kernel/fpu/init.c
index 7b2978ab30df..3a45fcd0b924 100644
--- a/arch/x86/kernel/fpu/init.c
+++ b/arch/x86/kernel/fpu/init.c
@@ -3,8 +3,11 @@
*/
#include <asm/fpu/internal.h>
#include <asm/tlbflush.h>
+#include <asm/setup.h>
+#include <asm/cmdline.h>
#include <linux/sched.h>
+#include <linux/init.h>
/*
* Initialize the TS bit in CR0 according to the style of context-switches
@@ -270,18 +273,6 @@ static void __init fpu__init_system_xstate_size_legacy(void)
*/
static enum { AUTO, ENABLE, DISABLE } eagerfpu = AUTO;
-static int __init eager_fpu_setup(char *s)
-{
- if (!strcmp(s, "on"))
- eagerfpu = ENABLE;
- else if (!strcmp(s, "off"))
- eagerfpu = DISABLE;
- else if (!strcmp(s, "auto"))
- eagerfpu = AUTO;
- return 1;
-}
-__setup("eagerfpu=", eager_fpu_setup);
-
/*
* Pick the FPU context switching strategy:
*/
@@ -316,11 +307,46 @@ static void __init fpu__init_system_ctx_switch(void)
}
/*
+ * We parse fpu parameters early because fpu__init_system() is executed
+ * before parse_early_param().
+ */
+static void __init fpu__init_parse_early_param(void)
+{
+ /*
+ * No need to check "eagerfpu=auto" again, since it is the
+ * initial default.
+ */
+ if (cmdline_find_option_bool(boot_command_line, "eagerfpu=off"))
+ eagerfpu = DISABLE;
+ else if (cmdline_find_option_bool(boot_command_line, "eagerfpu=on"))
+ eagerfpu = ENABLE;
+
+ if (cmdline_find_option_bool(boot_command_line, "no387"))
+ setup_clear_cpu_cap(X86_FEATURE_FPU);
+
+ if (cmdline_find_option_bool(boot_command_line, "nofxsr")) {
+ setup_clear_cpu_cap(X86_FEATURE_FXSR);
+ setup_clear_cpu_cap(X86_FEATURE_FXSR_OPT);
+ setup_clear_cpu_cap(X86_FEATURE_XMM);
+ }
+
+ if (cmdline_find_option_bool(boot_command_line, "noxsave"))
+ fpu__xstate_clear_all_cpu_caps();
+
+ if (cmdline_find_option_bool(boot_command_line, "noxsaveopt"))
+ setup_clear_cpu_cap(X86_FEATURE_XSAVEOPT);
+
+ if (cmdline_find_option_bool(boot_command_line, "noxsaves"))
+ setup_clear_cpu_cap(X86_FEATURE_XSAVES);
+}
+
+/*
* Called on the boot CPU once per system bootup, to set up the initial
* FPU state that is later cloned into all processes:
*/
void __init fpu__init_system(struct cpuinfo_x86 *c)
{
+ fpu__init_parse_early_param();
fpu__init_system_early_generic(c);
/*
@@ -344,62 +370,3 @@ void __init fpu__init_system(struct cpuinfo_x86 *c)
fpu__init_system_ctx_switch();
}
-
-/*
- * Boot parameter to turn off FPU support and fall back to math-emu:
- */
-static int __init no_387(char *s)
-{
- setup_clear_cpu_cap(X86_FEATURE_FPU);
- return 1;
-}
-__setup("no387", no_387);
-
-/*
- * Disable all xstate CPU features:
- */
-static int __init x86_noxsave_setup(char *s)
-{
- if (strlen(s))
- return 0;
-
- fpu__xstate_clear_all_cpu_caps();
-
- return 1;
-}
-__setup("noxsave", x86_noxsave_setup);
-
-/*
- * Disable the XSAVEOPT instruction specifically:
- */
-static int __init x86_noxsaveopt_setup(char *s)
-{
- setup_clear_cpu_cap(X86_FEATURE_XSAVEOPT);
-
- return 1;
-}
-__setup("noxsaveopt", x86_noxsaveopt_setup);
-
-/*
- * Disable the XSAVES instruction:
- */
-static int __init x86_noxsaves_setup(char *s)
-{
- setup_clear_cpu_cap(X86_FEATURE_XSAVES);
-
- return 1;
-}
-__setup("noxsaves", x86_noxsaves_setup);
-
-/*
- * Disable FX save/restore and SSE support:
- */
-static int __init x86_nofxsr_setup(char *s)
-{
- setup_clear_cpu_cap(X86_FEATURE_FXSR);
- setup_clear_cpu_cap(X86_FEATURE_FXSR_OPT);
- setup_clear_cpu_cap(X86_FEATURE_XMM);
-
- return 1;
-}
-__setup("nofxsr", x86_nofxsr_setup);