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u-boot/examples/standalone/stubs.c
Lukas Auer 7eb792970e riscv: support standalone applications on RV64I systems 
Add an implementation of EXPORT_FUNC() for RV64I systems to support them
in standalone applications.

Signed-off-by: Lukas Auer <lukas.auer@aisec.fraunhofer.de>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Tested-by: Bin Meng <bmeng.cn@gmail.com>
2019-01-15 09:36:31 +08:00

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#include <common.h>
#include <exports.h>
#include <linux/compiler.h>
#define FO(x) offsetof(struct jt_funcs, x)
#if defined(CONFIG_X86)
/*
* x86 does not have a dedicated register to store the pointer to
* the global_data. Thus the jump table address is stored in a
* global variable, but such approach does not allow for execution
* from flash memory. The global_data address is passed as argv[-1]
* to the application program.
*/
static struct jt_funcs *jt;
gd_t *global_data;
#define EXPORT_FUNC(f, a, x, ...) \
asm volatile ( \
" .globl " #x "\n" \
#x ":\n" \
" movl %0, %%eax\n" \
" movl jt, %%ecx\n" \
" jmp *(%%ecx, %%eax)\n" \
: : "i"(FO(x)) : "eax", "ecx");
#elif defined(CONFIG_PPC)
/*
* r2 holds the pointer to the global_data, r11 is a call-clobbered
* register
*/
#define EXPORT_FUNC(f, a, x, ...) \
asm volatile ( \
" .globl " #x "\n" \
#x ":\n" \
" lwz %%r11, %0(%%r2)\n" \
" lwz %%r11, %1(%%r11)\n" \
" mtctr %%r11\n" \
" bctr\n" \
: : "i"(offsetof(gd_t, jt)), "i"(FO(x)) : "r11");
#elif defined(CONFIG_ARM)
#ifdef CONFIG_ARM64
/*
* x18 holds the pointer to the global_data, x9 is a call-clobbered
* register
*/
#define EXPORT_FUNC(f, a, x, ...) \
asm volatile ( \
" .globl " #x "\n" \
#x ":\n" \
" ldr x9, [x18, %0]\n" \
" ldr x9, [x9, %1]\n" \
" br x9\n" \
: : "i"(offsetof(gd_t, jt)), "i"(FO(x)) : "x9");
#else
/*
* r9 holds the pointer to the global_data, ip is a call-clobbered
* register
*/
#define EXPORT_FUNC(f, a, x, ...) \
asm volatile ( \
" .globl " #x "\n" \
#x ":\n" \
" ldr ip, [r9, %0]\n" \
" ldr pc, [ip, %1]\n" \
: : "i"(offsetof(gd_t, jt)), "i"(FO(x)) : "ip");
#endif
#elif defined(CONFIG_MIPS)
#ifdef CONFIG_CPU_MIPS64
/*
* k0 ($26) holds the pointer to the global_data; t9 ($25) is a call-
* clobbered register that is also used to set gp ($26). Note that the
* jr instruction also executes the instruction immediately following
* it; however, GCC/mips generates an additional `nop' after each asm
* statement
*/
#define EXPORT_FUNC(f, a, x, ...) \
asm volatile ( \
" .globl " #x "\n" \
#x ":\n" \
" ld $25, %0($26)\n" \
" ld $25, %1($25)\n" \
" jr $25\n" \
: : "i"(offsetof(gd_t, jt)), "i"(FO(x)) : "t9");
#else
/*
* k0 ($26) holds the pointer to the global_data; t9 ($25) is a call-
* clobbered register that is also used to set gp ($26). Note that the
* jr instruction also executes the instruction immediately following
* it; however, GCC/mips generates an additional `nop' after each asm
* statement
*/
#define EXPORT_FUNC(f, a, x, ...) \
asm volatile ( \
" .globl " #x "\n" \
#x ":\n" \
" lw $25, %0($26)\n" \
" lw $25, %1($25)\n" \
" jr $25\n" \
: : "i"(offsetof(gd_t, jt)), "i"(FO(x)) : "t9");
#endif
#elif defined(CONFIG_NIOS2)
/*
* gp holds the pointer to the global_data, r8 is call-clobbered
*/
#define EXPORT_FUNC(f, a, x, ...) \
asm volatile ( \
" .globl " #x "\n" \
#x ":\n" \
" movhi r8, %%hi(%0)\n" \
" ori r8, r0, %%lo(%0)\n" \
" add r8, r8, gp\n" \
" ldw r8, 0(r8)\n" \
" ldw r8, %1(r8)\n" \
" jmp r8\n" \
: : "i"(offsetof(gd_t, jt)), "i"(FO(x)) : "gp");
#elif defined(CONFIG_M68K)
/*
* d7 holds the pointer to the global_data, a0 is a call-clobbered
* register
*/
#define EXPORT_FUNC(f, a, x, ...) \
asm volatile ( \
" .globl " #x "\n" \
#x ":\n" \
" move.l %%d7, %%a0\n" \
" adda.l %0, %%a0\n" \
" move.l (%%a0), %%a0\n" \
" adda.l %1, %%a0\n" \
" move.l (%%a0), %%a0\n" \
" jmp (%%a0)\n" \
: : "i"(offsetof(gd_t, jt)), "i"(FO(x)) : "a0");
#elif defined(CONFIG_MICROBLAZE)
/*
* r31 holds the pointer to the global_data. r5 is a call-clobbered.
*/
#define EXPORT_FUNC(f, a, x, ...) \
asm volatile ( \
" .globl " #x "\n" \
#x ":\n" \
" lwi r5, r31, %0\n" \
" lwi r5, r5, %1\n" \
" bra r5\n" \
: : "i"(offsetof(gd_t, jt)), "i"(FO(x)) : "r5");
#elif defined(CONFIG_SH)
/*
* r13 holds the pointer to the global_data. r1 is a call clobbered.
*/
#define EXPORT_FUNC(f, a, x, ...) \
asm volatile ( \
" .align 2\n" \
" .globl " #x "\n" \
#x ":\n" \
" mov r13, r1\n" \
" add %0, r1\n" \
" mov.l @r1, r2\n" \
" add %1, r2\n" \
" mov.l @r2, r1\n" \
" jmp @r1\n" \
" nop\n" \
" nop\n" \
: : "i"(offsetof(gd_t, jt)), "i"(FO(x)) : "r1", "r2");
#elif defined(CONFIG_NDS32)
/*
* r16 holds the pointer to the global_data. gp is call clobbered.
* not support reduced register (16 GPR).
*/
#define EXPORT_FUNC(f, a, x, ...) \
asm volatile ( \
" .globl " #x "\n" \
#x ":\n" \
" lwi $r16, [$gp + (%0)]\n" \
" lwi $r16, [$r16 + (%1)]\n" \
" jr $r16\n" \
: : "i"(offsetof(gd_t, jt)), "i"(FO(x)) : "$r16");
#elif defined(CONFIG_RISCV)
/*
* gp holds the pointer to the global_data. t0 is call clobbered.
*/
#ifdef CONFIG_ARCH_RV64I
#define EXPORT_FUNC(f, a, x, ...) \
asm volatile ( \
" .globl " #x "\n" \
#x ":\n" \
" ld t0, %0(gp)\n" \
" ld t0, %1(t0)\n" \
" jr t0\n" \
: : "i"(offsetof(gd_t, jt)), "i"(FO(x)) : "t0");
#else
#define EXPORT_FUNC(f, a, x, ...) \
asm volatile ( \
" .globl " #x "\n" \
#x ":\n" \
" lw t0, %0(gp)\n" \
" lw t0, %1(t0)\n" \
" jr t0\n" \
: : "i"(offsetof(gd_t, jt)), "i"(FO(x)) : "t0");
#endif
#elif defined(CONFIG_ARC)
/*
* r25 holds the pointer to the global_data. r10 is call clobbered.
*/
#define EXPORT_FUNC(f, a, x, ...) \
asm volatile( \
" .align 4\n" \
" .globl " #x "\n" \
#x ":\n" \
" ld r10, [r25, %0]\n" \
" ld r10, [r10, %1]\n" \
" j [r10]\n" \
: : "i"(offsetof(gd_t, jt)), "i"(FO(x)) : "r10");
#elif defined(CONFIG_XTENSA)
/*
* Global data ptr is in global_data, jump table ptr is in jt.
* Windowed ABI: Jump just past 'entry' in target and adjust stack frame
* (extract stack frame size from target 'entry' instruction).
*/
static void **jt;
#if defined(__XTENSA_CALL0_ABI__)
#define EXPORT_FUNC(f, a, x, ...) \
asm volatile ( \
" .extern jt\n" \
" .globl " #x "\n" \
" .align 4\n" \
#x ":\n" \
" l32i a8, %0, 0\n" \
" l32i a8, a8, %1\n" \
" jx a8\n" \
: : "r"(jt), "i" (FO(x)) : "a8");
#elif defined(__XTENSA_WINDOWED_ABI__)
#if XCHAL_HAVE_BE
# define SFT "8"
#else
# define SFT "12"
#endif
#define EXPORT_FUNC(f, a, x, ...) \
asm volatile ( \
" .extern jt\n" \
" .globl " #x "\n" \
" .align 4\n" \
#x ":\n" \
" entry sp, 16\n" \
" l32i a8, %0, 0\n" \
" l32i a8, a8, %1\n" \
" l32i a9, a8, 0\n" \
" extui a9, a9, " SFT ", 12\n" \
" subx8 a9, a9, sp\n" \
" movi a10, 16\n" \
" sub a9, a10, a9\n" \
" movsp sp, a9\n" \
" addi a8, a8, 3\n" \
" jx a8\n" \
: : "r"(jt), "i" (FO(x)) : "a8", "a9", "a10");
#else
#error Unsupported Xtensa ABI
#endif
#else
/*" addi $sp, $sp, -24\n" \
" br $r16\n" \*/
#error stubs definition missing for this architecture
#endif
/* This function is necessary to prevent the compiler from
* generating prologue/epilogue, preparing stack frame etc.
* The stub functions are special, they do not use the stack
* frame passed to them, but pass it intact to the actual
* implementation. On the other hand, asm() statements with
* arguments can be used only inside the functions (gcc limitation)
*/
#if GCC_VERSION < 30400
static
#endif /* GCC_VERSION */
void __attribute__((unused)) dummy(void)
{
#include <_exports.h>
}
#include <asm/sections.h>
void app_startup(char * const *argv)
{
char *cp = __bss_start;
/* Zero out BSS */
while (cp < _end)
*cp++ = 0;
#if defined(CONFIG_X86)
/* x86 does not have a dedicated register for passing global_data */
global_data = (gd_t *)argv[-1];
jt = global_data->jt;
#endif
}
#undef EXPORT_FUNC
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