To quit an EFI application we will need logic to jump to the caller of a function without returning from the function we called into, so we need setjmp/longjmp functionality.
This patch introduces a trivial implementation of these that I verified works on armv7, thumb2 and aarch64.
Signed-off-by: Alexander Graf agraf@suse.de --- arch/arm/include/asm/setjmp.h | 99 +++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 99 insertions(+) create mode 100644 arch/arm/include/asm/setjmp.h
diff --git a/arch/arm/include/asm/setjmp.h b/arch/arm/include/asm/setjmp.h new file mode 100644 index 0000000..b8b85b7 --- /dev/null +++ b/arch/arm/include/asm/setjmp.h @@ -0,0 +1,99 @@ +/* + * (C) Copyright 2016 + * Alexander Graf agraf@suse.de + * + * SPDX-License-Identifier: GPL-2.0+ + */ + +#ifndef _SETJMP_H_ +#define _SETJMP_H_ 1 + +struct jmp_buf_data { + ulong target; + ulong regs[5]; +}; + +typedef struct jmp_buf_data jmp_buf[1]; + +static inline int setjmp(jmp_buf jmp) +{ + long r = 0; + +#ifdef CONFIG_ARM64 + asm volatile( + "adr x1, jmp_target\n" + "str x1, %1\n" + "stp x26, x27, %2\n" + "stp x28, x29, %3\n" + "mov x1, sp\n" + "str x1, %4\n" + "b 2f\n" + "jmp_target: " + "mov %0, #1\n" + "2:\n" + : "+r" (r), "=m" (jmp->target), + "=m" (jmp->regs[0]), "=m" (jmp->regs[2]), + "=m" (jmp->regs[4]) + : + : "x0", "x1", "x2", "x3", "x4", "x5", "x6", "x7", + "x8", "x9", "x10", "x11", "x12", "x13", "x14", "x15", + "x16", "x17", "x18", "x19", "x20", "x21", "x22", + "x23", "x24", "x25", /* x26, x27, x28, x29, sp */ + "x30", "cc", "memory"); +#else + asm volatile( +#ifdef CONFIG_SYS_THUMB_BUILD + "adr r0, jmp_target + 1\n" +#else + "adr r0, jmp_target\n" +#endif + "mov r1, %1\n" + "mov r2, sp\n" + "stm r1, {r0, r2, r4, r5, r6, r7}\n" + "b 2f\n" + "jmp_target: " + "mov %0, #1\n" + "2:\n" + : "+l" (r) + : "l" (&jmp->target) + : "r0", "r1", "r2", "r3", /* "r4", "r5", "r6", "r7", */ + "r8", "r9", "r10", "r11", /* sp, */ "ip", "lr", + "cc", "memory"); +#endif + +printf("%s:%d target=%#lx\n", __func__, __LINE__, jmp->target); + + return r; +} + +static inline __noreturn void longjmp(jmp_buf jmp) +{ +#ifdef CONFIG_ARM64 + asm volatile( + "ldr x0, %0\n" + "ldr x1, %3\n" + "mov sp, x1\n" + "ldp x26, x27, %1\n" + "ldp x28, x25, %2\n" + "mov x29, x25\n" + "br x0\n" + : + : "m" (jmp->target), "m" (jmp->regs[0]), "m" (jmp->regs[2]), + "m" (jmp->regs[4]) + : "x0", "x1", "x25", "x26", "x27", "x28"); +#else + asm volatile( + "mov r1, %0\n" + "ldm r1, {r0, r2, r4, r5, r6, r7}\n" + "mov sp, r2\n" + "bx r0\n" + : + : "l" (&jmp->target) + : "r1"); +#endif + + while (1) { } +} + + +#endif /* _SETJMP_H_ */