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| author | Josh Boyer <jwboyer@linux.vnet.ibm.com> | 2009-08-19 04:27:53 +0000 |
|---|---|---|
| committer | Benjamin Herrenschmidt <benh@kernel.crashing.org> | 2009-08-27 13:12:52 +1000 |
| commit | 14d757520a08d09745c3b18bb34addd9bef56e2d (patch) | |
| tree | b75c1f6d29cb0439bef6fdf8bf2332987e573083 /arch/powerpc/kernel/misc_32.S | |
| parent | ea3cc330ac0cd521ff07c7cd432a1848c19a7e92 (diff) | |
| download | lwn-14d757520a08d09745c3b18bb34addd9bef56e2d.tar.gz lwn-14d757520a08d09745c3b18bb34addd9bef56e2d.zip | |
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/kernel/misc_32.S')
| -rw-r--r-- | arch/powerpc/kernel/misc_32.S | 7 |
1 files changed, 7 insertions, 0 deletions
diff --git a/arch/powerpc/kernel/misc_32.S b/arch/powerpc/kernel/misc_32.S index 15f28e0de78d..da9c0c4c10f3 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 |