diff options
author | Daniel Glöckner <dg@emlix.com> | 2009-03-04 13:42:27 -0500 |
---|---|---|
committer | Ingo Molnar <mingo@elte.hu> | 2009-03-04 14:33:16 -0500 |
commit | ab9e18587f4cdb5f3fb3854c732f27a36f98e8f6 (patch) | |
tree | b8d77d5fbdbdf919e4c0134762ff36ef11626802 /arch/x86/include/asm/i387.h | |
parent | dd39ecf522ba86c70809715af46e6557f6491131 (diff) |
x86, math-emu: fix init_fpu for task != current
Impact: fix math-emu related crash while using GDB/ptrace
init_fpu() calls finit to initialize a task's xstate, while finit always
works on the current task. If we use PTRACE_GETFPREGS on another
process and both processes did not already use floating point, we get
a null pointer exception in finit.
This patch creates a new function finit_task that takes a task_struct
parameter. finit becomes a wrapper that simply calls finit_task with
current. On the plus side this avoids many calls to get_current which
would each resolve to an inline assembler mov instruction.
An empty finit_task has been added to i387.h to avoid linker errors in
case the compiler still emits the call in init_fpu when
CONFIG_MATH_EMULATION is not defined.
The declaration of finit in i387.h has been removed as the remaining
code using this function gets its prototype from fpu_proto.h.
Signed-off-by: Daniel Glöckner <dg@emlix.com>
Cc: Suresh Siddha <suresh.b.siddha@intel.com>
Cc: "Pallipadi Venkatesh" <venkatesh.pallipadi@intel.com>
Cc: Arjan van de Ven <arjan@infradead.org>
Cc: Bill Metzenthen <billm@melbpc.org.au>
LKML-Reference: <E1Lew31-0004il-Fg@mailer.emlix.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'arch/x86/include/asm/i387.h')
-rw-r--r-- | arch/x86/include/asm/i387.h | 8 |
1 files changed, 7 insertions, 1 deletions
diff --git a/arch/x86/include/asm/i387.h b/arch/x86/include/asm/i387.h index 48f0004db8c9..71c9e5183982 100644 --- a/arch/x86/include/asm/i387.h +++ b/arch/x86/include/asm/i387.h | |||
@@ -172,7 +172,13 @@ static inline void __save_init_fpu(struct task_struct *tsk) | |||
172 | 172 | ||
173 | #else /* CONFIG_X86_32 */ | 173 | #else /* CONFIG_X86_32 */ |
174 | 174 | ||
175 | extern void finit(void); | 175 | #ifdef CONFIG_MATH_EMULATION |
176 | extern void finit_task(struct task_struct *tsk); | ||
177 | #else | ||
178 | static inline void finit_task(struct task_struct *tsk) | ||
179 | { | ||
180 | } | ||
181 | #endif | ||
176 | 182 | ||
177 | static inline void tolerant_fwait(void) | 183 | static inline void tolerant_fwait(void) |
178 | { | 184 | { |