From: Nicolas Pitre Date: Fri, 28 Jul 2017 22:48:48 +0000 (-0400) Subject: ARM: start_thread(): don't always clear all regs X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=5e5881143297c97207486349ec1cf9fd833b1510;p=linux.git 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 Acked-by: Mickael GUENE Tested-by: Vincent Abriou Tested-by: Andras Szemzo --- diff --git a/arch/arm/include/asm/processor.h b/arch/arm/include/asm/processor.h index c3d5fc124a054..338cbe0a18efe 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 */