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[PATCH v6 12/22] target/arm: default SVE length to 64 bytes for linux-us
From: |
Alex Bennée |
Subject: |
[PATCH v6 12/22] target/arm: default SVE length to 64 bytes for linux-user |
Date: |
Wed, 5 Feb 2020 17:10:21 +0000 |
The Linux kernel chooses the default of 64 bytes for SVE registers on
the basis that it is the largest size on known hardware that won't
grow the signal frame. We still honour the sve-max-vq property and
userspace can expand the number of lanes by calling PR_SVE_SET_VL.
This should not make any difference to SVE enabled software as the SVE
is of course vector length agnostic.
Signed-off-by: Alex Bennée <address@hidden>
Reviewed-by: Richard Henderson <address@hidden>
---
v2
- tweak zcr_el[1] instead
---
target/arm/cpu.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/target/arm/cpu.c b/target/arm/cpu.c
index f86e71a260d..e5eac981b0a 100644
--- a/target/arm/cpu.c
+++ b/target/arm/cpu.c
@@ -199,9 +199,9 @@ static void arm_cpu_reset(CPUState *s)
/* and to the SVE instructions */
env->cp15.cpacr_el1 = deposit64(env->cp15.cpacr_el1, 16, 2, 3);
env->cp15.cptr_el[3] |= CPTR_EZ;
- /* with maximum vector length */
+ /* with reasonable vector length */
env->vfp.zcr_el[1] = cpu_isar_feature(aa64_sve, cpu) ?
- cpu->sve_max_vq - 1 : 0;
+ MIN(cpu->sve_max_vq - 1, 3) : 0;
env->vfp.zcr_el[2] = env->vfp.zcr_el[1];
env->vfp.zcr_el[3] = env->vfp.zcr_el[1];
/*
--
2.20.1
- Re: [PATCH v6 13/22] target/arm: generate xml description of our SVE registers, (continued)
- [PATCH v6 17/22] tests/guest-debug: add a simple test runner, Alex Bennée, 2020/02/05
- [PATCH v6 09/22] gdbstub: extend GByteArray to read register helpers, Alex Bennée, 2020/02/05
- [PATCH v6 22/22] gdbstub: do not split gdb_monitor_write payload, Alex Bennée, 2020/02/05
- [PATCH v6 15/22] tests/tcg/aarch64: userspace system register test, Alex Bennée, 2020/02/05
- [PATCH v6 21/22] gdbstub: change GDBState.last_packet to GByteArray, Alex Bennée, 2020/02/05
- [PATCH v6 11/22] target/arm: explicitly encode regnum in our XML, Alex Bennée, 2020/02/05
- [PATCH v6 20/22] tests/tcg/aarch64: add test-sve-ioctl guest-debug test, Alex Bennée, 2020/02/05
- [PATCH v6 19/22] tests/tcg/aarch64: add SVE iotcl test, Alex Bennée, 2020/02/05
- [PATCH v6 12/22] target/arm: default SVE length to 64 bytes for linux-user,
Alex Bennée <=
- [PATCH v6 18/22] tests/tcg/aarch64: add a gdbstub testcase for SVE registers, Alex Bennée, 2020/02/05
- Re: [PATCH v6 00/22] gdbstub refactor and SVE support, no-reply, 2020/02/05