uml: kernel segfaults should dump proper registers
If there's a segfault inside the kernel, we want a dump of the registers at
the point of the segfault, not the registers at the point of calling panic or
the last userspace registers.
sig_handler_common_skas now uses a static register set in the case of a
SIGSEGV to avoid messing up the process registers if the segfault turns out to
be non-fatal.
The architecture sigcontext-to-pt_regs copying code was repurposed to copy
data out of the SEGV stack frame.
Signed-off-by: Jeff Dike <jdike@linux.intel.com>
Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/arch/um/sys-x86_64/signal.c b/arch/um/sys-x86_64/signal.c
index 0680062..fe8ec04 100644
--- a/arch/um/sys-x86_64/signal.c
+++ b/arch/um/sys-x86_64/signal.c
@@ -20,6 +20,36 @@
#include "skas.h"
+void copy_sc(union uml_pt_regs *regs, void *from)
+{
+ struct sigcontext *sc = from;
+
+#define GETREG(regs, regno, sc, regname) \
+ (regs)->skas.regs[(regno) / sizeof(unsigned long)] = (sc)->regname
+
+ GETREG(regs, R8, sc, r8);
+ GETREG(regs, R9, sc, r9);
+ GETREG(regs, R10, sc, r10);
+ GETREG(regs, R11, sc, r11);
+ GETREG(regs, R12, sc, r12);
+ GETREG(regs, R13, sc, r13);
+ GETREG(regs, R14, sc, r14);
+ GETREG(regs, R15, sc, r15);
+ GETREG(regs, RDI, sc, rdi);
+ GETREG(regs, RSI, sc, rsi);
+ GETREG(regs, RBP, sc, rbp);
+ GETREG(regs, RBX, sc, rbx);
+ GETREG(regs, RDX, sc, rdx);
+ GETREG(regs, RAX, sc, rax);
+ GETREG(regs, RCX, sc, rcx);
+ GETREG(regs, RSP, sc, rsp);
+ GETREG(regs, RIP, sc, rip);
+ GETREG(regs, EFLAGS, sc, eflags);
+ GETREG(regs, CS, sc, cs);
+
+#undef GETREG
+}
+
static int copy_sc_from_user_skas(struct pt_regs *regs,
struct sigcontext __user *from)
{
