From: Peter Maydell <peter.maydell@linaro.org>
To: qemu-devel@nongnu.org
Subject: [Qemu-devel] [PULL 17/24] arm: Thumb shift operations should not permit interworking branches
Date: Thu, 20 Apr 2017 17:41:03 +0100 [thread overview]
Message-ID: <1492706470-10921-18-git-send-email-peter.maydell@linaro.org> (raw)
In-Reply-To: <1492706470-10921-1-git-send-email-peter.maydell@linaro.org>
In Thumb mode, the only instructions which can cause an interworking
branch by writing the PC are BLX, BX, BXJ, LDR, POP and LDM. Unlike
ARM mode, data processing instructions which target the PC do not
cause interworking branches.
When we added support for doing interworking branches on writes to
PC from data processing instructions in commit 21aeb3430ce7ba, we
accidentally changed a Thumb instruction to have interworking
branch behaviour for writes to PC. (MOV, MOVS register-shifted
register, encoding T2; this is the standard encoding for
LSL/LSR/ASR/ROR (register).)
For this encoding, behaviour with Rd == R15 is specified as
UNPREDICTABLE, so allowing an interworking branch is within
spec, but it's confusing and differs from our handling of this
class of UNPREDICTABLE for other Thumb ALU operations. Make
it perform a simple (non-interworking) branch like the others.
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <rth@twiddle.net>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Message-id: 1491844419-12485-3-git-send-email-peter.maydell@linaro.org
---
target/arm/translate.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/target/arm/translate.c b/target/arm/translate.c
index fe3f442..ddc62b6 100644
--- a/target/arm/translate.c
+++ b/target/arm/translate.c
@@ -9959,7 +9959,7 @@ static int disas_thumb2_insn(CPUARMState *env, DisasContext *s, uint16_t insn_hw
gen_arm_shift_reg(tmp, op, tmp2, logic_cc);
if (logic_cc)
gen_logic_CC(tmp);
- store_reg_bx(s, rd, tmp);
+ store_reg(s, rd, tmp);
break;
case 1: /* Sign/zero extend. */
op = (insn >> 20) & 7;
--
2.7.4
next prev parent reply other threads:[~2017-04-20 16:41 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-04-20 16:40 [Qemu-devel] [PULL 00/24] target-arm queue Peter Maydell
2017-04-20 16:40 ` [Qemu-devel] [PULL 01/24] hw/arm/boot: take Linux/arm64 TEXT_OFFSET header field into account Peter Maydell
2017-04-20 16:40 ` [Qemu-devel] [PULL 02/24] hw/arm/exynos: Convert fprintf to qemu_log_mask/error_report Peter Maydell
2017-04-20 16:40 ` [Qemu-devel] [PULL 03/24] hw/char/exynos4210_uart: Constify static array and few arguments Peter Maydell
2017-04-20 16:40 ` [Qemu-devel] [PULL 04/24] hw/misc/exynos4210_pmu: Reorder local variables for readability Peter Maydell
2017-04-20 16:40 ` [Qemu-devel] [PULL 05/24] target/arm: Add missing entries to excnames[] for log strings Peter Maydell
2017-04-20 16:40 ` [Qemu-devel] [PULL 06/24] arm: Move excnames[] array into arm_log_exceptions() Peter Maydell
2017-04-20 16:40 ` [Qemu-devel] [PULL 07/24] target/arm: Add assertion about FSC format for syndrome registers Peter Maydell
2017-04-20 16:40 ` [Qemu-devel] [PULL 08/24] stellaris: Don't hw_error() on bad register accesses Peter Maydell
2017-04-20 16:40 ` [Qemu-devel] [PULL 09/24] arm/kvm: Remove trailing newlines from error_report() Peter Maydell
2017-04-20 16:40 ` [Qemu-devel] [PULL 10/24] hw/arm: Qomify pxa2xx.c Peter Maydell
2017-04-20 16:40 ` [Qemu-devel] [PULL 11/24] cadence_gem: Read the correct queue descriptor Peter Maydell
2017-04-20 16:40 ` [Qemu-devel] [PULL 12/24] cadence_gem: Correct the multi-queue can rx logic Peter Maydell
2017-04-20 16:40 ` [Qemu-devel] [PULL 13/24] cadence_gem: Correct the interupt logic Peter Maydell
2017-04-20 16:41 ` [Qemu-devel] [PULL 14/24] cadence_gem: Make the revision a property Peter Maydell
2017-04-20 16:41 ` [Qemu-devel] [PULL 15/24] xlnx-zynqmp: Set the Cadence GEM revision Peter Maydell
2017-04-20 16:41 ` [Qemu-devel] [PULL 16/24] arm: Don't implement BXJ on M-profile CPUs Peter Maydell
2017-04-20 16:41 ` Peter Maydell [this message]
2017-04-20 16:41 ` [Qemu-devel] [PULL 18/24] arm: Factor out "generate right kind of step exception" Peter Maydell
2017-04-20 16:41 ` [Qemu-devel] [PULL 19/24] arm: Move gen_set_condexec() and gen_set_pc_im() up in the file Peter Maydell
2017-04-20 16:41 ` [Qemu-devel] [PULL 20/24] arm: Move condition-failed codepath generation out of if() Peter Maydell
2017-04-20 16:41 ` [Qemu-devel] [PULL 21/24] arm: Abstract out "are we singlestepping" test to utility function Peter Maydell
2017-04-20 16:41 ` [Qemu-devel] [PULL 22/24] arm: Track M profile handler mode state in TB flags Peter Maydell
2017-04-20 16:41 ` [Qemu-devel] [PULL 23/24] arm: Implement M profile exception return properly Peter Maydell
2017-04-20 16:41 ` [Qemu-devel] [PULL 24/24] arm: Remove workarounds for old M-profile exception return implementation Peter Maydell
2017-04-20 17:30 ` [Qemu-devel] [PULL 00/24] target-arm queue Peter Maydell
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