[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
[PATCH v2 05/57] target/arm: Let vfp_access_check() handle late NOCP che
From: |
Peter Maydell |
Subject: |
[PATCH v2 05/57] target/arm: Let vfp_access_check() handle late NOCP checks |
Date: |
Mon, 14 Jun 2021 16:09:15 +0100 |
In commit a3494d4671797c we reworked the M-profile handling of its
checks for when the NOCP exception should be raised because the FPU
is disabled, so that (in line with the architecture) the NOCP check
is done early over a large range of the encoding space, and takes
precedence over UNDEF exceptions. As part of this, we removed the
code from full_vfp_access_check() which raised an exception there for
M-profile with the FPU disabled, because it was no longer reachable.
For MVE, some instructions which are outside the "coprocessor space"
region of the encoding space must nonetheless do "is the FPU enabled"
checks and possibly raise a NOCP exception. (In particular this
covers the MVE-specific low-overhead branch insns LCTP, DLSTP and
WLSTP.) To support these insns, reinstate the code in
full_vfp_access_check(), so that their trans functions can call
vfp_access_check() and get the correct behaviour.
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
---
target/arm/translate-vfp.c | 20 +++++++++++++++-----
1 file changed, 15 insertions(+), 5 deletions(-)
diff --git a/target/arm/translate-vfp.c b/target/arm/translate-vfp.c
index 2e12c694edc..01e26a246d6 100644
--- a/target/arm/translate-vfp.c
+++ b/target/arm/translate-vfp.c
@@ -143,11 +143,21 @@ static void gen_preserve_fp_state(DisasContext *s)
static bool full_vfp_access_check(DisasContext *s, bool ignore_vfp_enabled)
{
if (s->fp_excp_el) {
- /* M-profile handled this earlier, in disas_m_nocp() */
- assert (!arm_dc_feature(s, ARM_FEATURE_M));
- gen_exception_insn(s, s->pc_curr, EXCP_UDEF,
- syn_fp_access_trap(1, 0xe, false),
- s->fp_excp_el);
+ if (arm_dc_feature(s, ARM_FEATURE_M)) {
+ /*
+ * M-profile mostly catches the "FPU disabled" case early, in
+ * disas_m_nocp(), but a few insns (eg LCTP, WLSTP, DLSTP)
+ * which do coprocessor-checks are outside the large ranges of
+ * the encoding space handled by the patterns in m-nocp.decode,
+ * and for them we may need to raise NOCP here.
+ */
+ gen_exception_insn(s, s->pc_curr, EXCP_NOCP,
+ syn_uncategorized(), s->fp_excp_el);
+ } else {
+ gen_exception_insn(s, s->pc_curr, EXCP_UDEF,
+ syn_fp_access_trap(1, 0xe, false),
+ s->fp_excp_el);
+ }
return false;
}
--
2.20.1
- [PATCH v2 00/57] target/arm: First slice of MVE implementation, Peter Maydell, 2021/06/14
- [PATCH v2 02/57] target/arm: Enable FPSCR.QC bit for MVE, Peter Maydell, 2021/06/14
- [PATCH v2 03/57] target/arm: Handle VPR semantics in existing code, Peter Maydell, 2021/06/14
- [PATCH v2 01/57] target/arm: Provide and use H8 and H1_8 macros, Peter Maydell, 2021/06/14
- [PATCH v2 04/57] target/arm: Add handling for PSR.ECI/ICI, Peter Maydell, 2021/06/14
- [PATCH v2 06/57] target/arm: Implement MVE LCTP, Peter Maydell, 2021/06/14
- [PATCH v2 07/57] target/arm: Implement MVE WLSTP insn, Peter Maydell, 2021/06/14
- [PATCH v2 05/57] target/arm: Let vfp_access_check() handle late NOCP checks,
Peter Maydell <=
- [PATCH v2 08/57] target/arm: Implement MVE DLSTP, Peter Maydell, 2021/06/14
- [PATCH v2 09/57] target/arm: Implement MVE LETP insn, Peter Maydell, 2021/06/14
- [PATCH v2 10/57] target/arm: Add framework for MVE decode, Peter Maydell, 2021/06/14
- [PATCH v2 11/57] target/arm: Implement MVE VLDR/VSTR (non-widening forms), Peter Maydell, 2021/06/14
- [PATCH v2 12/57] target/arm: Implement widening/narrowing MVE VLDR/VSTR insns, Peter Maydell, 2021/06/14
- [PATCH v2 16/57] bitops.h: Provide hswap32(), hswap64(), wswap64() swapping operations, Peter Maydell, 2021/06/14
- [PATCH v2 17/57] target/arm: Implement MVE VREV16, VREV32, VREV64, Peter Maydell, 2021/06/14