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>
diff --git a/arch/arm/include/asm/processor.h b/arch/arm/include/asm/processor.h
index c3d5fc1..338cbe0 100644
--- a/arch/arm/include/asm/processor.h
+++ b/arch/arm/include/asm/processor.h
@@ -47,15 +47,24 @@
#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 @@
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 */