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authorNicolas Pitre <nicolas.pitre@linaro.org>2017-07-29 01:48:48 +0300
committerNicolas Pitre <nicolas.pitre@linaro.org>2017-09-11 02:31:46 +0300
commit5e5881143297c97207486349ec1cf9fd833b1510 (patch)
tree539dcbb787d1f4435dd9e452b652c649eff199c0
parente71fd63127c5a1d4fb7660f5d4cbc257374a2af9 (diff)
downloadlinux-5e5881143297c97207486349ec1cf9fd833b1510.tar.xz
ARM: start_thread(): don't always clear all regs
The elf_fdpic binary format driver has to initialize extra registers beside the stack and program counter as required by the corresponding ABI. So reinstate them after the regs structure has been cleared. While at it let's get rid of start_thread_nommu(). Signed-off-by: Nicolas Pitre <nico@linaro.org> Acked-by: Mickael GUENE <mickael.guene@st.com> Tested-by: Vincent Abriou <vincent.abriou@st.com> Tested-by: Andras Szemzo <szemzo.andras@gmail.com>
-rw-r--r--arch/arm/include/asm/processor.h22
1 files changed, 15 insertions, 7 deletions
diff --git a/arch/arm/include/asm/processor.h b/arch/arm/include/asm/processor.h
index c3d5fc124a05..338cbe0a18ef 100644
--- a/arch/arm/include/asm/processor.h
+++ b/arch/arm/include/asm/processor.h
@@ -47,15 +47,24 @@ struct thread_struct {
#define INIT_THREAD { }
-#ifdef CONFIG_MMU
-#define nommu_start_thread(regs) do { } while (0)
-#else
-#define nommu_start_thread(regs) regs->ARM_r10 = current->mm->start_data
-#endif
-
#define start_thread(regs,pc,sp) \
({ \
+ unsigned long r7, r8, r9; \
+ \
+ if (IS_ENABLED(CONFIG_BINFMT_ELF_FDPIC)) { \
+ r7 = regs->ARM_r7; \
+ r8 = regs->ARM_r8; \
+ r9 = regs->ARM_r9; \
+ } \
memset(regs->uregs, 0, sizeof(regs->uregs)); \
+ if (IS_ENABLED(CONFIG_BINFMT_ELF_FDPIC) && \
+ current->personality & FDPIC_FUNCPTRS) { \
+ regs->ARM_r7 = r7; \
+ regs->ARM_r8 = r8; \
+ regs->ARM_r9 = r9; \
+ regs->ARM_r10 = current->mm->start_data; \
+ } else if (!IS_ENABLED(CONFIG_MMU)) \
+ regs->ARM_r10 = current->mm->start_data; \
if (current->personality & ADDR_LIMIT_32BIT) \
regs->ARM_cpsr = USR_MODE; \
else \
@@ -65,7 +74,6 @@ struct thread_struct {
regs->ARM_cpsr |= PSR_ENDSTATE; \
regs->ARM_pc = pc & ~1; /* pc */ \
regs->ARM_sp = sp; /* sp */ \
- nommu_start_thread(regs); \
})
/* Forward declaration, a strange C thing */