diff options
| author | Juergen Gross <jgross@suse.com> | 2015-08-06 20:54:34 +0300 |
|---|---|---|
| committer | Ben Hutchings <ben@decadent.org.uk> | 2015-10-13 05:46:03 +0300 |
| commit | e73256664c4ad969637021b1f3a9bea2dc6fdd17 (patch) | |
| tree | 1c37fb8466fe0627a2067d550977ed76e4ec1882 /arch | |
| parent | 75a146b383c8b5175bc313ee73ebe6f9afb248c9 (diff) | |
| download | linux-e73256664c4ad969637021b1f3a9bea2dc6fdd17.tar.xz | |
x86/ldt: Correct FPU emulation access to LDT
commit 4809146b86c3d41ce588fdb767d021e2a80600dd upstream.
Commit 37868fe113ff ("x86/ldt: Make modify_ldt synchronous")
introduced a new struct ldt_struct anchored at mm->context.ldt.
Adapt the x86 fpu emulation code to use that new structure.
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Andy Lutomirski <luto@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: billm@melbpc.org.au
Link: http://lkml.kernel.org/r/1438883674-1240-1-git-send-email-jgross@suse.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
[bwh: Backported to 3.2: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/x86/math-emu/fpu_entry.c | 3 | ||||
| -rw-r--r-- | arch/x86/math-emu/fpu_system.h | 21 | ||||
| -rw-r--r-- | arch/x86/math-emu/get_address.c | 3 |
3 files changed, 20 insertions, 7 deletions
diff --git a/arch/x86/math-emu/fpu_entry.c b/arch/x86/math-emu/fpu_entry.c index 7718541541d4..dab1f8b8fb1c 100644 --- a/arch/x86/math-emu/fpu_entry.c +++ b/arch/x86/math-emu/fpu_entry.c @@ -28,7 +28,6 @@ #include <linux/regset.h> #include <asm/uaccess.h> -#include <asm/desc.h> #include <asm/user.h> #include <asm/i387.h> @@ -184,7 +183,7 @@ void math_emulate(struct math_emu_info *info) math_abort(FPU_info, SIGILL); } - code_descriptor = LDT_DESCRIPTOR(FPU_CS); + code_descriptor = FPU_get_ldt_descriptor(FPU_CS); if (SEG_D_SIZE(code_descriptor)) { /* The above test may be wrong, the book is not clear */ /* Segmented 32 bit protected mode */ diff --git a/arch/x86/math-emu/fpu_system.h b/arch/x86/math-emu/fpu_system.h index 2c614410a5f3..d342fce49447 100644 --- a/arch/x86/math-emu/fpu_system.h +++ b/arch/x86/math-emu/fpu_system.h @@ -16,9 +16,24 @@ #include <linux/kernel.h> #include <linux/mm.h> -/* s is always from a cpu register, and the cpu does bounds checking - * during register load --> no further bounds checks needed */ -#define LDT_DESCRIPTOR(s) (((struct desc_struct *)current->mm->context.ldt)[(s) >> 3]) +#include <asm/desc.h> +#include <asm/mmu_context.h> + +static inline struct desc_struct FPU_get_ldt_descriptor(unsigned seg) +{ + static struct desc_struct zero_desc; + struct desc_struct ret = zero_desc; + +#ifdef CONFIG_MODIFY_LDT_SYSCALL + seg >>= 3; + mutex_lock(¤t->mm->context.lock); + if (current->mm->context.ldt && seg < current->mm->context.ldt->size) + ret = current->mm->context.ldt->entries[seg]; + mutex_unlock(¤t->mm->context.lock); +#endif + return ret; +} + #define SEG_D_SIZE(x) ((x).b & (3 << 21)) #define SEG_G_BIT(x) ((x).b & (1 << 23)) #define SEG_GRANULARITY(x) (((x).b & (1 << 23)) ? 4096 : 1) diff --git a/arch/x86/math-emu/get_address.c b/arch/x86/math-emu/get_address.c index 6ef5e99380f9..d13cab2aec45 100644 --- a/arch/x86/math-emu/get_address.c +++ b/arch/x86/math-emu/get_address.c @@ -20,7 +20,6 @@ #include <linux/stddef.h> #include <asm/uaccess.h> -#include <asm/desc.h> #include "fpu_system.h" #include "exception.h" @@ -158,7 +157,7 @@ static long pm_address(u_char FPU_modrm, u_char segment, addr->selector = PM_REG_(segment); } - descriptor = LDT_DESCRIPTOR(PM_REG_(segment)); + descriptor = FPU_get_ldt_descriptor(segment); base_address = SEG_BASE_ADDR(descriptor); address = base_address + offset; limit = base_address |