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parisc: Fix patch code locking and flushing 

This change fixes the following:

1) The flags variable is not initialized. Always use raw_spin_lock_irqsave
and raw_spin_unlock_irqrestore to serialize patching.

2) flush_kernel_vmap_range is primarily intended for DMA flushes. Since
__patch_text_multiple is often called with interrupts disabled, it is
better to directly call flush_kernel_dcache_range_asm and
flush_kernel_icache_range_asm. This avoids an extra call.

3) The final call to flush_icache_range is unnecessary.

Signed-off-by: John David Anglin <dave.anglin@bell.net>
Signed-off-by: Helge Deller <deller@gmx.de>
This commit is contained in:
John David Anglin 2022-03-29 18:54:36 +00:00 committed by Helge Deller
parent 1afde47d08
commit a9fe7fa7d8
1 changed files with 11 additions and 14 deletions
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25
arch/parisc/kernel/patch.c
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@ -40,10 +40,7 @@ static void __kprobes *patch_map(void *addr, int fixmap, unsigned long *flags,
*need_unmap = 1;
set_fixmap(fixmap, page_to_phys(page));
if (flags)
raw_spin_lock_irqsave(&patch_lock, *flags);
else
__acquire(&patch_lock);
raw_spin_lock_irqsave(&patch_lock, *flags);
return (void *) (__fix_to_virt(fixmap) + (uintaddr & ~PAGE_MASK));
}
@ -52,10 +49,7 @@ static void __kprobes patch_unmap(int fixmap, unsigned long *flags)
{
clear_fixmap(fixmap);
if (flags)
raw_spin_unlock_irqrestore(&patch_lock, *flags);
else
__release(&patch_lock);
raw_spin_unlock_irqrestore(&patch_lock, *flags);
}
void __kprobes __patch_text_multiple(void *addr, u32 *insn, unsigned int len)
@ -67,8 +61,9 @@ void __kprobes __patch_text_multiple(void *addr, u32 *insn, unsigned int len)
int mapped;
/* Make sure we don't have any aliases in cache */
flush_kernel_vmap_range(addr, len);
flush_icache_range(start, end);
flush_kernel_dcache_range_asm(start, end);
flush_kernel_icache_range_asm(start, end);
flush_tlb_kernel_range(start, end);
p = fixmap = patch_map(addr, FIX_TEXT_POKE0, &flags, &mapped);
@ -81,8 +76,10 @@ void __kprobes __patch_text_multiple(void *addr, u32 *insn, unsigned int len)
* We're crossing a page boundary, so
* need to remap
*/
flush_kernel_vmap_range((void *)fixmap,
(p-fixmap) * sizeof(*p));
flush_kernel_dcache_range_asm((unsigned long)fixmap,
(unsigned long)p);
flush_tlb_kernel_range((unsigned long)fixmap,
(unsigned long)p);
if (mapped)
patch_unmap(FIX_TEXT_POKE0, &flags);
p = fixmap = patch_map(addr, FIX_TEXT_POKE0, &flags,
@ -90,10 +87,10 @@ void __kprobes __patch_text_multiple(void *addr, u32 *insn, unsigned int len)
}
}
flush_kernel_vmap_range((void *)fixmap, (p-fixmap) * sizeof(*p));
flush_kernel_dcache_range_asm((unsigned long)fixmap, (unsigned long)p);
flush_tlb_kernel_range((unsigned long)fixmap, (unsigned long)p);
if (mapped)
patch_unmap(FIX_TEXT_POKE0, &flags);
flush_icache_range(start, end);
}
void __kprobes __patch_text(void *addr, u32 insn)