This is a note to let you know that I've just added the patch titled

powerpc/64: Fix flush_(d|i)cache_range() called from modules

to the 4.4-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git%3Ba=su...

The filename of the patch is: powerpc-64-fix-flush_-d-i-cache_range-called-from-modules.patch and it can be found in the queue-4.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let stable@vger.kernel.org know about it.

From 8f5f525d5b83f7d76a6baf9c4e94d4bf312ea7f6 Mon Sep 17 00:00:00 2001

From: Oliver O'Halloran oohall@gmail.com Date: Mon, 3 Apr 2017 13:25:12 +1000 Subject: powerpc/64: Fix flush_(d|i)cache_range() called from modules

From: Oliver O'Halloran oohall@gmail.com

commit 8f5f525d5b83f7d76a6baf9c4e94d4bf312ea7f6 upstream.

When the kernel is compiled to use 64bit ABIv2 the _GLOBAL() macro does not include a global entry point. A function's global entry point is used when the function is called from a different TOC context and in the kernel this typically means a call from a module into the vmlinux (or vice-versa).

There are a few exported asm functions declared with _GLOBAL() and calling them from a module will likely crash the kernel since any TOC relative load will yield garbage.

flush_icache_range() and flush_dcache_range() are both exported to modules, and use the TOC, so must use _GLOBAL_TOC().

Fixes: 721aeaa9fdf3 ("powerpc: Build little endian ppc64 kernel with ABIv2") Signed-off-by: Oliver O'Halloran oohall@gmail.com Signed-off-by: Michael Ellerman mpe@ellerman.id.au Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org

--- arch/powerpc/include/asm/ppc_asm.h | 12 ++++++++++++ arch/powerpc/kernel/misc_64.S | 4 ++-- 2 files changed, 14 insertions(+), 2 deletions(-)

--- a/arch/powerpc/include/asm/ppc_asm.h +++ b/arch/powerpc/include/asm/ppc_asm.h @@ -224,6 +224,16 @@ name: \ .globl name; \ name:

+#define _KPROBE_TOC(name) \ + .section ".kprobes.text","a"; \ + .align 2 ; \ + .type name,@function; \ + .globl name; \ +name: \ +0: addis r2,r12,(.TOC.-0b)@ha; \ + addi r2,r2,(.TOC.-0b)@l; \ + .localentry name,.-name + #define DOTSYM(a) a

#else @@ -261,6 +271,8 @@ name: \ .type GLUE(.,name),@function; \ GLUE(.,name):

+#define _KPROBE_TOC(n) _KPROBE(n) + #define DOTSYM(a) GLUE(.,a)

#endif --- a/arch/powerpc/kernel/misc_64.S +++ b/arch/powerpc/kernel/misc_64.S @@ -66,7 +66,7 @@ PPC64_CACHES: * flush all bytes from start through stop-1 inclusive */

-_KPROBE(flush_icache_range) +_KPROBE_TOC(flush_icache_range) BEGIN_FTR_SECTION PURGE_PREFETCHED_INS blr @@ -117,7 +117,7 @@ END_FTR_SECTION_IFSET(CPU_FTR_COHERENT_I * * flush all bytes from start to stop-1 inclusive */ -_GLOBAL(flush_dcache_range) +_GLOBAL_TOC(flush_dcache_range)

/* * Flush the data cache to memory

Patches currently in stable-queue which might be from oohall@gmail.com are

queue-4.4/powerpc-64-fix-flush_-d-i-cache_range-called-from-modules.patch queue-4.4/powerpc-powernv-check-device-tree-for-rfi-flush-settings.patch