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Commit 14d75752 authored by Josh Boyer's avatar Josh Boyer Committed by Benjamin Herrenschmidt
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powerpc: Fix __flush_icache_range on 44x 



The ptrace POKETEXT interface allows a process to modify the text pages of
a child process being ptraced, usually to insert breakpoints via trap
instructions.  The kernel eventually calls copy_to_user_page, which in turn
calls __flush_icache_range to invalidate the icache lines for the child
process.

However, this function does not work on 44x due to the icache being virtually
indexed.  This was noticed by a breakpoint being triggered after it had been
cleared by ltrace on a 440EPx board.  The convenient solution is to do a
flash invalidate of the icache in the __flush_icache_range function.

Signed-off-by: default avatarJosh Boyer <jwboyer@linux.vnet.ibm.com>
Signed-off-by: default avatarBenjamin Herrenschmidt <benh@kernel.crashing.org>
parent ea3cc330

arch/powerpc/kernel/misc_32.S

+7 −0
Original line number Diff line number Diff line
@@ -342,10 +342,17 @@ END_FTR_SECTION_IFSET(CPU_FTR_COHERENT_ICACHE) 
	addi	r3,r3,L1_CACHE_BYTES

	bdnz	1b

	sync				/* wait for dcbst's to get to ram */

#ifndef CONFIG_44x

	mtctr	r4

2:	icbi	0,r6

	addi	r6,r6,L1_CACHE_BYTES

	bdnz	2b

#else

	/* Flash invalidate on 44x because we are passed kmapped addresses and

	   this doesn't work for userspace pages due to the virtually tagged

	   icache.  Sigh. */

	iccci	0, r0

#endif

	sync				/* additional sync needed on g4 */

	isync

	blr