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Subject[PATCH 50 of 55] xen64: save lots of registers
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The Xen hypercall interface is allowed to trash any or all of the
argument registers, so we need to be careful that the kernel state
isn't damaged. On 32-bit kernels, the hypercall parameter registers
same as a regparm function call, so we've got away without explicit
clobbering so far. The 64-bit ABI defines lots of caller-save
registers, so save them all for safety. We can trim this set later by
re-distributing the responsibility for saving all these registers.

Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
---
include/asm-x86/paravirt.h | 26 ++++++++++++++++++++++----
1 file changed, 22 insertions(+), 4 deletions(-)

diff --git a/include/asm-x86/paravirt.h b/include/asm-x86/paravirt.h
--- a/include/asm-x86/paravirt.h
+++ b/include/asm-x86/paravirt.h
@@ -1396,8 +1396,8 @@
* caller saved registers but the argument parameter */
#define PV_SAVE_REGS "pushq %%rdi;"
#define PV_RESTORE_REGS "popq %%rdi;"
-#define PV_EXTRA_CLOBBERS EXTRA_CLOBBERS, "rcx" , "rdx"
-#define PV_VEXTRA_CLOBBERS EXTRA_CLOBBERS, "rdi", "rcx" , "rdx"
+#define PV_EXTRA_CLOBBERS EXTRA_CLOBBERS, "rcx" , "rdx", "rsi"
+#define PV_VEXTRA_CLOBBERS EXTRA_CLOBBERS, "rdi", "rcx" , "rdx", "rsi"
#define PV_FLAGS_ARG "D"
#endif

@@ -1489,8 +1489,26 @@


#ifdef CONFIG_X86_64
-#define PV_SAVE_REGS pushq %rax; pushq %rdi; pushq %rcx; pushq %rdx
-#define PV_RESTORE_REGS popq %rdx; popq %rcx; popq %rdi; popq %rax
+#define PV_SAVE_REGS \
+ push %rax; \
+ push %rcx; \
+ push %rdx; \
+ push %rsi; \
+ push %rdi; \
+ push %r8; \
+ push %r9; \
+ push %r10; \
+ push %r11
+#define PV_RESTORE_REGS \
+ pop %r11; \
+ pop %r10; \
+ pop %r9; \
+ pop %r8; \
+ pop %rdi; \
+ pop %rsi; \
+ pop %rdx; \
+ pop %rcx; \
+ pop %rax
#define PARA_PATCH(struct, off) ((PARAVIRT_PATCH_##struct + (off)) / 8)
#define PARA_SITE(ptype, clobbers, ops) _PVSITE(ptype, clobbers, ops, .quad, 8)
#define PARA_INDIRECT(addr) *addr(%rip)



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