[V2 PATCH 1/3] powerpc: Enable emulate_step In Little Endian Mode
From: Tom <hidden>
Date: 2013-10-31 18:39:45
Subsystem:
linux for powerpc (32-bit and 64-bit), the rest · Maintainers:
Madhavan Srinivasan, Michael Ellerman, Linus Torvalds
From: Tom Musta <redacted> This patch modifies the endian chicken switch in the single step emulation code (emulate_step()). The old (big endian) code bailed early if a load or store instruction was to be emulated in little endian mode. The new code modifies the check and only bails in a cross-endian situation (LE mode in a kernel compiled for BE and vice verse). V2: fixed bug in MSR[LE] check identified by Andreas Schwab and Geert Uytterhoeven. Signed-off-by: Tom Musta <redacted> --- arch/powerpc/lib/sstep.c | 12 +++++++++--- 1 files changed, 9 insertions(+), 3 deletions(-)
diff --git a/arch/powerpc/lib/sstep.c b/arch/powerpc/lib/sstep.c
index b1faa15..7bfaa9d 100644
--- a/arch/powerpc/lib/sstep.c
+++ b/arch/powerpc/lib/sstep.c@@ -1222,12 +1222,18 @@ int __kprobes emulate_step(struct pt_regs *regs, unsigned int instr) } /* - * Following cases are for loads and stores, so bail out - * if we're in little-endian mode. + * Following cases are for loads and stores and this + * implementation does not support cross-endian. So + * bail out if this is the case. */ +#ifdef __BIG_ENDIAN__ if (regs->msr & MSR_LE) return 0; - +#endif +#ifdef __LITTLE_ENDIAN__ + if (!(regs->msr & MSR_LE)) + return 0; +#endif /* * Save register RA in case it's an update form load or store * and the access faults.
--
1.7.1