x86: Add implementations of setjmp() and longjmp()
Bring in these functions from Linux v4.4. They will be needed for EFI loader
support.
Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
diff --git a/arch/x86/cpu/setjmp.S b/arch/x86/cpu/setjmp.S
new file mode 100644
index 0000000..2ea1c6c
--- /dev/null
+++ b/arch/x86/cpu/setjmp.S
@@ -0,0 +1,61 @@
+/*
+ * Written by H. Peter Anvin <hpa@zytor.com>
+ * Brought in from Linux v4.4 and modified for U-Boot
+ * From Linux arch/um/sys-i386/setjmp.S
+ *
+ * SPDX-License-Identifier: GPL-2.0
+ */
+
+#define _REGPARM
+
+/*
+ * The jmp_buf is assumed to contain the following, in order:
+ * %ebx
+ * %esp
+ * %ebp
+ * %esi
+ * %edi
+ * <return address>
+ */
+
+ .text
+ .align 4
+ .globl setjmp
+ .type setjmp, @function
+setjmp:
+#ifdef _REGPARM
+ movl %eax, %edx
+#else
+ movl 4(%esp), %edx
+#endif
+ popl %ecx /* Return address, and adjust the stack */
+ xorl %eax, %eax /* Return value */
+ movl %ebx, (%edx)
+ movl %esp, 4(%edx) /* Post-return %esp! */
+ pushl %ecx /* Make the call/return stack happy */
+ movl %ebp, 8(%edx)
+ movl %esi, 12(%edx)
+ movl %edi, 16(%edx)
+ movl %ecx, 20(%edx) /* Return address */
+ ret
+
+ /* Provide function size if needed */
+ .size setjmp, .-setjmp
+
+ .align 4
+ .globl longjmp
+ .type longjmp, @function
+longjmp:
+#ifdef _REGPARM
+ xchgl %eax, %edx
+#else
+ movl 4(%esp), %edx /* jmp_ptr address */
+#endif
+ movl (%edx), %ebx
+ movl 4(%edx), %esp
+ movl 8(%edx), %ebp
+ movl 12(%edx), %esi
+ movl 16(%edx), %edi
+ jmp *20(%edx)
+
+ .size longjmp, .-longjmp