Commit 7e923369 authored by Sven Schnelle's avatar Sven Schnelle Committed by Helge Deller
Browse files

parisc: add spinlock to patch function 



If multiple CPUs are patching code we need the spinlock
to protect against parallel fixmap maps/unmap calls.

Signed-off-by: default avatarSven Schnelle <svens@stackframe.org>
Signed-off-by: default avatarHelge Deller <deller@gmx.de>
parent 4e87ace9

arch/parisc/kernel/patch.c

+19 −6
Original line number Diff line number Diff line
@@ -23,7 +23,9 @@ struct patch { 


static DEFINE_RAW_SPINLOCK(patch_lock);



static void __kprobes *patch_map(void *addr, int fixmap, int *need_unmap)

static void __kprobes *patch_map(void *addr, int fixmap, unsigned long *flags,

				 int *need_unmap)

{

	unsigned long uintaddr = (uintptr_t) addr;

	bool module = !core_kernel_text(uintaddr);

	struct page *page;
@@ -38,19 +40,29 @@ static void __kprobes *patch_map(void *addr, int fixmap, int *need_unmap) 


	*need_unmap = 1;

	set_fixmap(fixmap, page_to_phys(page));

	if (flags)

		raw_spin_lock_irqsave(&patch_lock, *flags);

	else

		__acquire(&patch_lock);



	return (void *) (__fix_to_virt(fixmap) + (uintaddr & ~PAGE_MASK));

}



static void __kprobes patch_unmap(int fixmap)

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);

}



void __kprobes __patch_text_multiple(void *addr, u32 *insn, unsigned int len)

{

	unsigned long start = (unsigned long)addr;

	unsigned long end = (unsigned long)addr + len;

	unsigned long flags;

	u32 *p, *fixmap;

	int mapped;
@@ -58,7 +70,7 @@ void __kprobes __patch_text_multiple(void *addr, u32 *insn, unsigned int len) 
	flush_kernel_vmap_range(addr, len);

	flush_icache_range(start, end);



	p = fixmap = patch_map(addr, FIX_TEXT_POKE0, &mapped);

	p = fixmap = patch_map(addr, FIX_TEXT_POKE0, &flags, &mapped);



	while (len >= 4) {

		*p++ = *insn++;
@@ -72,14 +84,15 @@ void __kprobes __patch_text_multiple(void *addr, u32 *insn, unsigned int len) 
			flush_kernel_vmap_range((void *)fixmap,

						(p-fixmap) * sizeof(*p));

			if (mapped)

				patch_unmap(FIX_TEXT_POKE0);

			p = fixmap = patch_map(addr, FIX_TEXT_POKE0, &mapped);

				patch_unmap(FIX_TEXT_POKE0, &flags);

			p = fixmap = patch_map(addr, FIX_TEXT_POKE0, &flags,

						&mapped);

		}

	}



	flush_kernel_vmap_range((void *)fixmap, (p-fixmap) * sizeof(*p));

	if (mapped)

		patch_unmap(FIX_TEXT_POKE0);

		patch_unmap(FIX_TEXT_POKE0, &flags);

	flush_icache_range(start, end);

}