[PATCH 5.16 147/285] parisc: Fix patch code locking and flushing

Greg Kroah-Hartman
2022-04-12T08:37:59Z

From: John David Anglin <dave.anglin@bell.net>

[ Upstream commit a9fe7fa7d874a536e0540469f314772c054a0323 ]

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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
arch/parisc/kernel/patch.c | 25 +++++++++++--------------
1 file changed, 11 insertions(+), 14 deletions(-)

diff --git a/arch/parisc/kernel/patch.c b/arch/parisc/kernel/patch.c
index 80a0ab372802..e59574f65e64 100644
--- a/arch/parisc/kernel/patch.c
+++ b/arch/parisc/kernel/patch.c
@@ -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)
--
2.35.1