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authorPeter Maydell <peter.maydell@linaro.org>2017-03-30 11:52:30 +0100
committerPeter Maydell <peter.maydell@linaro.org>2017-04-03 12:59:14 +0100
commit709a340d679d95a0c6cbb9b5f654498f04345b50 (patch)
tree696ed93f00169508b696f0d3a6917df7c2f4023a
parentf9e46d37bd19b4f3faaedb78a48c53d02ee4197e (diff)
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tcg/sparc: Zero extend data argument to store helpers
The C store helper functions take the data argument as a uint8_t, uint16_t, etc depending on the store size. The SPARC calling convention requires that data types smaller than the register size must be extended by the caller. We weren't doing this, which meant that if QEMU was compiled with optimizations enabled we could end up storing incorrect values to guest memory. (In particular the i386 guest BIOS would crash on startup.) Add code to the trampolines that call the store helpers to do the zero extension as required. Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org> Message-id: 1490871151-29029-2-git-send-email-peter.maydell@linaro.org Reviewed-by: Richard Henderson <rth@twiddle.net>
-rw-r--r--tcg/sparc/tcg-target.inc.c25
1 files changed, 25 insertions, 0 deletions
diff --git a/tcg/sparc/tcg-target.inc.c b/tcg/sparc/tcg-target.inc.c
index d1f4c0d..ab34039 100644
--- a/tcg/sparc/tcg-target.inc.c
+++ b/tcg/sparc/tcg-target.inc.c
@@ -843,6 +843,29 @@ static void tcg_out_mb(TCGContext *s, TCGArg a0)
static tcg_insn_unit *qemu_ld_trampoline[16];
static tcg_insn_unit *qemu_st_trampoline[16];
+static void emit_extend(TCGContext *s, TCGReg r, int op)
+{
+ /* Emit zero extend of 8, 16 or 32 bit data as
+ * required by the MO_* value op; do nothing for 64 bit.
+ */
+ switch (op & MO_SIZE) {
+ case MO_8:
+ tcg_out_arithi(s, r, r, 0xff, ARITH_AND);
+ break;
+ case MO_16:
+ tcg_out_arithi(s, r, r, 16, SHIFT_SLL);
+ tcg_out_arithi(s, r, r, 16, SHIFT_SRL);
+ break;
+ case MO_32:
+ if (SPARC64) {
+ tcg_out_arith(s, r, r, 0, SHIFT_SRL);
+ }
+ break;
+ case MO_64:
+ break;
+ }
+}
+
static void build_trampolines(TCGContext *s)
{
static void * const qemu_ld_helpers[16] = {
@@ -910,6 +933,7 @@ static void build_trampolines(TCGContext *s)
qemu_st_trampoline[i] = s->code_ptr;
if (SPARC64) {
+ emit_extend(s, TCG_REG_O2, i);
ra = TCG_REG_O4;
} else {
ra = TCG_REG_O1;
@@ -925,6 +949,7 @@ static void build_trampolines(TCGContext *s)
tcg_out_arithi(s, ra, ra + 1, 32, SHIFT_SRLX);
ra += 2;
} else {
+ emit_extend(s, ra, i);
ra += 1;
}
/* Skip the oi argument. */