Static tramp v5 (#624)

[platform/upstream/libffi.git] / src / aarch64 / sysv.S

diff --git a/src/aarch64/sysv.S b/src/aarch64/sysv.S
index b720a92..a3c1508 100644 (file)
--- a/src/aarch64/sysv.S
+++ b/src/aarch64/sysv.S
@@ -367,6 +367,76 @@ CNAME(ffi_closure_SYSV):
        .size   CNAME(ffi_closure_SYSV), . - CNAME(ffi_closure_SYSV)
 #endif
 
+#if defined(FFI_EXEC_STATIC_TRAMP)
+       .align 4
+CNAME(ffi_closure_SYSV_V_alt):
+       /* See the comments above trampoline_code_table. */
+       ldr     x17, [sp, #8]                   /* Load closure in x17 */
+       add     sp, sp, #16                     /* Restore the stack */
+       b       CNAME(ffi_closure_SYSV_V)
+
+       .globl  CNAME(ffi_closure_SYSV_V_alt)
+       FFI_HIDDEN(CNAME(ffi_closure_SYSV_V_alt))
+#ifdef __ELF__
+       .type   CNAME(ffi_closure_SYSV_V_alt), #function
+       .size   CNAME(ffi_closure_SYSV_V_alt), . - CNAME(ffi_closure_SYSV_V_alt)
+#endif
+
+       .align 4
+CNAME(ffi_closure_SYSV_alt):
+       /* See the comments above trampoline_code_table. */
+       ldr     x17, [sp, #8]                   /* Load closure in x17 */
+       add     sp, sp, #16                     /* Restore the stack */
+       b       CNAME(ffi_closure_SYSV)
+
+       .globl  CNAME(ffi_closure_SYSV_alt)
+       FFI_HIDDEN(CNAME(ffi_closure_SYSV_alt))
+#ifdef __ELF__
+       .type   CNAME(ffi_closure_SYSV_alt), #function
+       .size   CNAME(ffi_closure_SYSV_alt), . - CNAME(ffi_closure_SYSV_alt)
+#endif
+
+/*
+ * Below is the definition of the trampoline code table. Each element in
+ * the code table is a trampoline.
+ */
+/*
+ * The trampoline uses register x17. It saves the original value of x17 on
+ * the stack.
+ *
+ * The trampoline has two parameters - target code to jump to and data for
+ * the target code. The trampoline extracts the parameters from its parameter
+ * block (see tramp_table_map()). The trampoline saves the data address on
+ * the stack. Finally, it jumps to the target code.
+ *
+ * The target code can choose to:
+ *
+ * - restore the value of x17
+ * - load the data address in a register
+ * - restore the stack pointer to what it was when the trampoline was invoked.
+ */
+       .align  AARCH64_TRAMP_MAP_SHIFT
+CNAME(trampoline_code_table):
+       .rept   AARCH64_TRAMP_MAP_SIZE / AARCH64_TRAMP_SIZE
+       sub     sp, sp, #16             /* Make space on the stack */
+       str     x17, [sp]               /* Save x17 on stack */
+       adr     x17, #16376             /* Get data address */
+       ldr     x17, [x17]              /* Copy data into x17 */
+       str     x17, [sp, #8]           /* Save data on stack */
+       adr     x17, #16372             /* Get code address */
+       ldr     x17, [x17]              /* Load code address into x17 */
+       br      x17                     /* Jump to code */
+       .endr
+
+       .globl CNAME(trampoline_code_table)
+       FFI_HIDDEN(CNAME(trampoline_code_table))
+#ifdef __ELF__
+       .type   CNAME(trampoline_code_table), #function
+       .size   CNAME(trampoline_code_table), . - CNAME(trampoline_code_table)
+#endif
+       .align  AARCH64_TRAMP_MAP_SHIFT
+#endif /* FFI_EXEC_STATIC_TRAMP */
+
 #if FFI_EXEC_TRAMPOLINE_TABLE
 
 #ifdef __MACH__