Commit 9bbafce2 authored by Paul Mundt's avatar Paul Mundt

sh: Fix occasional FPU register corruption under preempt.

Presently with preempt enabled there's the possibility to be preempted
after the TIF_USEDFPU test and the register save, leading to bogus
state post-__switch_to(). Use an explicit preempt_disable()/enable()
pair around unlazy_fpu()/clear_fpu() to avoid this. Follows the x86
change.
Reported-by: default avatarTakuo Koguchi <takuo.koguchi.sw@hitachi.com>
Signed-off-by: default avatarPaul Mundt <lethal@linux-sh.org>
parent 05dda977
...@@ -13,6 +13,7 @@ ...@@ -13,6 +13,7 @@
#include <linux/signal.h> #include <linux/signal.h>
#include <asm/processor.h> #include <asm/processor.h>
#include <asm/io.h> #include <asm/io.h>
#include <asm/fpu.h>
/* The PR (precision) bit in the FP Status Register must be clear when /* The PR (precision) bit in the FP Status Register must be clear when
* an frchg instruction is executed, otherwise the instruction is undefined. * an frchg instruction is executed, otherwise the instruction is undefined.
......
...@@ -16,6 +16,7 @@ ...@@ -16,6 +16,7 @@
#include <asm/cpu/fpu.h> #include <asm/cpu/fpu.h>
#include <asm/processor.h> #include <asm/processor.h>
#include <asm/system.h> #include <asm/system.h>
#include <asm/fpu.h>
/* The PR (precision) bit in the FP Status Register must be clear when /* The PR (precision) bit in the FP Status Register must be clear when
* an frchg instruction is executed, otherwise the instruction is undefined. * an frchg instruction is executed, otherwise the instruction is undefined.
......
...@@ -17,6 +17,7 @@ ...@@ -17,6 +17,7 @@
#include <asm/processor.h> #include <asm/processor.h>
#include <asm/user.h> #include <asm/user.h>
#include <asm/io.h> #include <asm/io.h>
#include <asm/fpu.h>
/* /*
* Initially load the FPU with signalling NANS. This bit pattern * Initially load the FPU with signalling NANS. This bit pattern
......
#include <linux/elfcore.h> #include <linux/elfcore.h>
#include <linux/sched.h> #include <linux/sched.h>
#include <asm/fpu.h>
/* /*
* Capture the user space registers if the task is not running (in user space) * Capture the user space registers if the task is not running (in user space)
......
...@@ -25,6 +25,7 @@ ...@@ -25,6 +25,7 @@
#include <asm/pgalloc.h> #include <asm/pgalloc.h>
#include <asm/system.h> #include <asm/system.h>
#include <asm/ubc.h> #include <asm/ubc.h>
#include <asm/fpu.h>
static int hlt_counter; static int hlt_counter;
int ubc_usercnt = 0; int ubc_usercnt = 0;
......
...@@ -29,6 +29,7 @@ ...@@ -29,6 +29,7 @@
#include <asm/uaccess.h> #include <asm/uaccess.h>
#include <asm/pgtable.h> #include <asm/pgtable.h>
#include <asm/cacheflush.h> #include <asm/cacheflush.h>
#include <asm/fpu.h>
#define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP))) #define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))
......
#ifndef __ASM_SH_FPU_H #ifndef __ASM_SH_FPU_H
#define __ASM_SH_FPU_H #define __ASM_SH_FPU_H
#define SR_FD 0x00008000
#ifndef __ASSEMBLY__ #ifndef __ASSEMBLY__
#include <linux/preempt.h>
#include <asm/ptrace.h> #include <asm/ptrace.h>
#ifdef CONFIG_SH_FPU #ifdef CONFIG_SH_FPU
...@@ -28,18 +27,23 @@ extern void save_fpu(struct task_struct *__tsk, struct pt_regs *regs); ...@@ -28,18 +27,23 @@ extern void save_fpu(struct task_struct *__tsk, struct pt_regs *regs);
extern int do_fpu_inst(unsigned short, struct pt_regs *); extern int do_fpu_inst(unsigned short, struct pt_regs *);
#define unlazy_fpu(tsk, regs) do { \ static inline void unlazy_fpu(struct task_struct *tsk, struct pt_regs *regs)
if (test_tsk_thread_flag(tsk, TIF_USEDFPU)) { \ {
save_fpu(tsk, regs); \ preempt_disable();
} \ if (test_tsk_thread_flag(tsk, TIF_USEDFPU))
} while (0) save_fpu(tsk, regs);
preempt_enable();
#define clear_fpu(tsk, regs) do { \ }
if (test_tsk_thread_flag(tsk, TIF_USEDFPU)) { \
clear_tsk_thread_flag(tsk, TIF_USEDFPU); \ static inline void clear_fpu(struct task_struct *tsk, struct pt_regs *regs)
release_fpu(regs); \ {
} \ preempt_disable();
} while (0) if (test_tsk_thread_flag(tsk, TIF_USEDFPU)) {
clear_tsk_thread_flag(tsk, TIF_USEDFPU);
release_fpu(regs);
}
preempt_enable();
}
#endif /* __ASSEMBLY__ */ #endif /* __ASSEMBLY__ */
......
...@@ -2,7 +2,6 @@ ...@@ -2,7 +2,6 @@
#define __ASM_SH_PROCESSOR_H #define __ASM_SH_PROCESSOR_H
#include <asm/cpu-features.h> #include <asm/cpu-features.h>
#include <asm/fpu.h>
#ifndef __ASSEMBLY__ #ifndef __ASSEMBLY__
/* /*
......
...@@ -70,6 +70,7 @@ extern struct sh_cpuinfo cpu_data[]; ...@@ -70,6 +70,7 @@ extern struct sh_cpuinfo cpu_data[];
*/ */
#define SR_DSP 0x00001000 #define SR_DSP 0x00001000
#define SR_IMASK 0x000000f0 #define SR_IMASK 0x000000f0
#define SR_FD 0x00008000
/* /*
* FPU structure and data * FPU structure and data
......
...@@ -112,6 +112,7 @@ extern struct sh_cpuinfo cpu_data[]; ...@@ -112,6 +112,7 @@ extern struct sh_cpuinfo cpu_data[];
#endif #endif
#define SR_IMASK 0x000000f0 #define SR_IMASK 0x000000f0
#define SR_FD 0x00008000
#define SR_SSTEP 0x08000000 #define SR_SSTEP 0x08000000
#ifndef __ASSEMBLY__ #ifndef __ASSEMBLY__
......
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