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[ARM] 3168/1: Update ARM signal delivery and masking 

Patch from Daniel Jacobowitz

After delivering a signal (creating its stack frame) we must check for
additional pending unblocked signals before returning to userspace.
Otherwise signals may be delayed past the next syscall or reschedule.

Once that was fixed it became obvious that the ARM signal mask manipulation
was broken.  It was a little bit broken before the recent SA_NODEFER
changes, and then very broken after them.  We must block the requested
signals before starting the handler or the same signal can be delivered
again before the handler even gets a chance to run.

Signed-off-by: Daniel Jacobowitz <dan@codesourcery.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
This commit is contained in:
Daniel Jacobowitz 2005-11-19 10:01:07 +00:00 committed by Russell King
parent d2c5b69099
commit a6c61e9dfd
4 changed files with 14 additions and 201 deletions
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3
arch/arm/kernel/entry-common.S
View File

@ -48,8 +48,7 @@ work_pending:
mov r0, sp @ 'regs'
mov r2, why @ 'syscall'
bl do_notify_resume
disable_irq @ disable interrupts
b no_work_pending
b ret_slow_syscall @ Check work again
work_resched:
bl schedule

25
arch/arm/kernel/signal.c
View File

@ -595,23 +595,22 @@ handle_signal(unsigned long sig, struct k_sigaction *ka,
*/
ret |= !valid_user_regs(regs);
/*
* Block the signal if we were unsuccessful.
*/
if (ret != 0) {
spin_lock_irq(&tsk->sighand->siglock);
sigorsets(&tsk->blocked, &tsk->blocked,
&ka->sa.sa_mask);
if (!(ka->sa.sa_flags & SA_NODEFER))
sigaddset(&tsk->blocked, sig);
recalc_sigpending();
spin_unlock_irq(&tsk->sighand->siglock);
force_sigsegv(sig, tsk);
return;
}
if (ret == 0)
return;
/*
* Block the signal if we were successful.
*/
spin_lock_irq(&tsk->sighand->siglock);
sigorsets(&tsk->blocked, &tsk->blocked,
&ka->sa.sa_mask);
if (!(ka->sa.sa_flags & SA_NODEFER))
sigaddset(&tsk->blocked, sig);
recalc_sigpending();
spin_unlock_irq(&tsk->sighand->siglock);
force_sigsegv(sig, tsk);
}
/*

2
arch/arm/mm/Makefile
View File

@ -51,4 +51,4 @@ obj-$(CONFIG_CPU_ARM1026) += proc-arm1026.o
obj-$(CONFIG_CPU_SA110) += proc-sa110.o
obj-$(CONFIG_CPU_SA1100) += proc-sa1100.o
obj-$(CONFIG_CPU_XSCALE) += proc-xscale.o
obj-$(CONFIG_CPU_V6) += proc-v6.o blockops.o
obj-$(CONFIG_CPU_V6) += proc-v6.o

185
arch/arm/mm/blockops.c
View File

@ -1,185 +0,0 @@
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/errno.h>
#include <linux/mm.h>
#include <asm/memory.h>
#include <asm/ptrace.h>
#include <asm/cacheflush.h>
#include <asm/traps.h>
extern struct cpu_cache_fns blk_cache_fns;
#define HARVARD_CACHE
/*
* blk_flush_kern_dcache_page(kaddr)
*
* Ensure that the data held in the page kaddr is written back
* to the page in question.
*
* - kaddr - kernel address (guaranteed to be page aligned)
*/
static void __attribute__((naked))
blk_flush_kern_dcache_page(void *kaddr)
{
asm(
"add r1, r0, %0 \n\
sub r1, r1, %1 \n\
1: .word 0xec401f0e @ mcrr p15, 0, r0, r1, c14, 0 @ blocking \n\
mov r0, #0 \n\
mcr p15, 0, r0, c7, c5, 0 \n\
mcr p15, 0, r0, c7, c10, 4 \n\
mov pc, lr"
:
: "I" (PAGE_SIZE), "I" (L1_CACHE_BYTES));
}
/*
* blk_dma_inv_range(start,end)
*
* Invalidate the data cache within the specified region; we will
* be performing a DMA operation in this region and we want to
* purge old data in the cache.
*
* - start - virtual start address of region
* - end - virtual end address of region
*/
static void __attribute__((naked))
blk_dma_inv_range_unified(unsigned long start, unsigned long end)
{
asm(
"tst r0, %0 \n\
mcrne p15, 0, r0, c7, c11, 1 @ clean unified line \n\
tst r1, %0 \n\
mcrne p15, 0, r1, c7, c15, 1 @ clean & invalidate unified line\n\
.word 0xec401f06 @ mcrr p15, 0, r1, r0, c6, 0 @ blocking \n\
mov r0, #0 \n\
mcr p15, 0, r0, c7, c10, 4 @ drain write buffer \n\
mov pc, lr"
:
: "I" (L1_CACHE_BYTES - 1));
}
static void __attribute__((naked))
blk_dma_inv_range_harvard(unsigned long start, unsigned long end)
{
asm(
"tst r0, %0 \n\
mcrne p15, 0, r0, c7, c10, 1 @ clean D line \n\
tst r1, %0 \n\
mcrne p15, 0, r1, c7, c14, 1 @ clean & invalidate D line \n\
.word 0xec401f06 @ mcrr p15, 0, r1, r0, c6, 0 @ blocking \n\
mov r0, #0 \n\
mcr p15, 0, r0, c7, c10, 4 @ drain write buffer \n\
mov pc, lr"
:
: "I" (L1_CACHE_BYTES - 1));
}
/*
* blk_dma_clean_range(start,end)
* - start - virtual start address of region
* - end - virtual end address of region
*/
static void __attribute__((naked))
blk_dma_clean_range(unsigned long start, unsigned long end)
{
asm(
".word 0xec401f0c @ mcrr p15, 0, r1, r0, c12, 0 @ blocking \n\
mov r0, #0 \n\
mcr p15, 0, r0, c7, c10, 4 @ drain write buffer \n\
mov pc, lr");
}
/*
* blk_dma_flush_range(start,end)
* - start - virtual start address of region
* - end - virtual end address of region
*/
static void __attribute__((naked))
blk_dma_flush_range(unsigned long start, unsigned long end)
{
asm(
".word 0xec401f0e @ mcrr p15, 0, r1, r0, c14, 0 @ blocking \n\
mov pc, lr");
}
static int blockops_trap(struct pt_regs *regs, unsigned int instr)
{
regs->ARM_r4 |= regs->ARM_r2;
regs->ARM_pc += 4;
return 0;
}
static char *func[] = {
"Prefetch data range",
"Clean+Invalidate data range",
"Clean data range",
"Invalidate data range",
"Invalidate instr range"
};
static struct undef_hook blockops_hook __initdata = {
.instr_mask = 0x0fffffd0,
.instr_val = 0x0c401f00,
.cpsr_mask = PSR_T_BIT,
.cpsr_val = 0,
.fn = blockops_trap,
};
static int __init blockops_check(void)
{
register unsigned int err asm("r4") = 0;
unsigned int err_pos = 1;
unsigned int cache_type;
int i;
asm("mrc p15, 0, %0, c0, c0, 1" : "=r" (cache_type));
printk("Checking V6 block cache operations:\n");
register_undef_hook(&blockops_hook);
__asm__ ("mov r0, %0\n\t"
"mov r1, %1\n\t"
"mov r2, #1\n\t"
".word 0xec401f2c @ mcrr p15, 0, r1, r0, c12, 2\n\t"
"mov r2, #2\n\t"
".word 0xec401f0e @ mcrr p15, 0, r1, r0, c14, 0\n\t"
"mov r2, #4\n\t"
".word 0xec401f0c @ mcrr p15, 0, r1, r0, c12, 0\n\t"
"mov r2, #8\n\t"
".word 0xec401f06 @ mcrr p15, 0, r1, r0, c6, 0\n\t"
"mov r2, #16\n\t"
".word 0xec401f05 @ mcrr p15, 0, r1, r0, c5, 0\n\t"
:
: "r" (PAGE_OFFSET), "r" (PAGE_OFFSET + 128)
: "r0", "r1", "r2");
unregister_undef_hook(&blockops_hook);
for (i = 0; i < ARRAY_SIZE(func); i++, err_pos <<= 1)
printk("%30s: %ssupported\n", func[i], err & err_pos ? "not " : "");
if ((err & 8) == 0) {
printk(" --> Using %s block cache invalidate\n",
cache_type & (1 << 24) ? "harvard" : "unified");
if (cache_type & (1 << 24))
cpu_cache.dma_inv_range = blk_dma_inv_range_harvard;
else
cpu_cache.dma_inv_range = blk_dma_inv_range_unified;
}
if ((err & 4) == 0) {
printk(" --> Using block cache clean\n");
cpu_cache.dma_clean_range = blk_dma_clean_range;
}
if ((err & 2) == 0) {
printk(" --> Using block cache clean+invalidate\n");
cpu_cache.dma_flush_range = blk_dma_flush_range;
cpu_cache.flush_kern_dcache_page = blk_flush_kern_dcache_page;
}
return 0;
}
__initcall(blockops_check);