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authorJosh Boyer <jwboyer@linux.vnet.ibm.com>2009-08-19 04:27:53 +0000
committerBenjamin Herrenschmidt <benh@kernel.crashing.org>2009-08-27 13:12:52 +1000
commit14d757520a08d09745c3b18bb34addd9bef56e2d (patch)
treeb75c1f6d29cb0439bef6fdf8bf2332987e573083 /arch/powerpc
parentea3cc330ac0cd521ff07c7cd432a1848c19a7e92 (diff)
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: Josh Boyer <jwboyer@linux.vnet.ibm.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Diffstat (limited to 'arch/powerpc')
-rw-r--r--arch/powerpc/kernel/misc_32.S7
1 files changed, 7 insertions, 0 deletions
diff --git a/arch/powerpc/kernel/misc_32.S b/arch/powerpc/kernel/misc_32.S
index 15f28e0de78..da9c0c4c10f 100644
--- a/arch/powerpc/kernel/misc_32.S
+++ b/arch/powerpc/kernel/misc_32.S
@@ -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