Clang prefers to use a "mempcy" (or equivalent) to copy the "regs"
structure. This doesn't work in 16-bit mode, as it will end up copying
over half the number of bytes. GCC performs a field-by-field copy of the
structure, so force clang to do the same thing.
Signed-off-by: Bill Wendling <morbo@xxxxxxxxxx>
---
x86/realmode.c | 19 ++++++++++++++++---
1 file changed, 16 insertions(+), 3 deletions(-)
diff --git a/x86/realmode.c b/x86/realmode.c
index 303d093..cf45fd6 100644
--- a/x86/realmode.c
+++ b/x86/realmode.c
@@ -117,6 +117,19 @@ struct regs {
u32 eip, eflags;
};
+#define COPY_REG(name, dst, src) (dst).name = (src).name
+#define COPY_REGS(dst, src) \
+ COPY_REG(eax, dst, src); \
+ COPY_REG(ebx, dst, src); \
+ COPY_REG(ecx, dst, src); \
+ COPY_REG(edx, dst, src); \
+ COPY_REG(esi, dst, src); \
+ COPY_REG(edi, dst, src); \
+ COPY_REG(esp, dst, src); \
+ COPY_REG(ebp, dst, src); \
+ COPY_REG(eip, dst, src); \
+ COPY_REG(eflags, dst, src)
+
struct table_descr {
u16 limit;
void *base;
@@ -148,11 +161,11 @@ static void exec_in_big_real_mode(struct insn_desc *insn)
extern u8 test_insn[], test_insn_end[];
for (i = 0; i < insn->len; ++i)
- test_insn[i] = ((u8 *)(unsigned long)insn->ptr)[i];
+ test_insn[i] = ((u8 *)(unsigned long)insn->ptr)[i];
for (; i < test_insn_end - test_insn; ++i)
test_insn[i] = 0x90; // nop
- save = inregs;
+ COPY_REGS(save, inregs);
asm volatile(
"lgdtl %[gdt_descr] \n\t"
"mov %%cr0, %[tmp] \n\t"
@@ -196,7 +209,7 @@ static void exec_in_big_real_mode(struct insn_desc *insn)
: [gdt_descr]"m"(gdt_descr), [bigseg]"r"((short)16)
: "cc", "memory"
);
- outregs = save;
+ COPY_REGS(outregs, save);
}
#define R_AX 1
--
2.23.0.700.g56cf767bdb-goog
