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target/arm: Split vfp_access_check() into A and M versions 

vfp_access_check and its helper routine full_vfp_access_check() has
gradually grown and is now an awkward mix of A-profile only and
M-profile only pieces.  Refactor it into an A-profile only and an
M-profile only version, taking advantage of the fact that now the
only direct call to full_vfp_access_check() is in A-profile-only
code.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20210618141019.10671-7-peter.maydell@linaro.org
This commit is contained in:
Peter Maydell 2021-06-18 15:10:18 +01:00
parent 95aceeeac9
commit e8cedaf779
1 changed files with 48 additions and 31 deletions
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79
target/arm/translate-vfp.c
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@ -188,32 +188,19 @@ static void gen_update_fp_context(DisasContext *s)
}
/*
* Check that VFP access is enabled. If it is, do the necessary
* M-profile lazy-FP handling and then return true.
* If not, emit code to generate an appropriate exception and
* return false.
* Check that VFP access is enabled, A-profile specific version.
*
* If VFP is enabled, return true. If not, emit code to generate an
* appropriate exception and return false.
* The ignore_vfp_enabled argument specifies that we should ignore
* whether VFP is enabled via FPEXC[EN]: this should be true for FMXR/FMRX
* whether VFP is enabled via FPEXC.EN: this should be true for FMXR/FMRX
* accesses to FPSID, FPEXC, MVFR0, MVFR1, MVFR2, and false for all other insns.
*/
static bool full_vfp_access_check(DisasContext *s, bool ignore_vfp_enabled)
static bool vfp_access_check_a(DisasContext *s, bool ignore_vfp_enabled)
{
if (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);
}
gen_exception_insn(s, s->pc_curr, EXCP_UDEF,
syn_fp_access_trap(1, 0xe, false), s->fp_excp_el);
return false;
}
@ -222,17 +209,39 @@ static bool full_vfp_access_check(DisasContext *s, bool ignore_vfp_enabled)
unallocated_encoding(s);
return false;
}
return true;
}
if (arm_dc_feature(s, ARM_FEATURE_M)) {
/* Handle M-profile lazy FP state mechanics */
/* Trigger lazy-state preservation if necessary */
gen_preserve_fp_state(s);
/* Update ownership of FP context and create new FP context if needed */
gen_update_fp_context(s);
/*
* Check that VFP access is enabled, M-profile specific version.
*
* If VFP is enabled, do the necessary M-profile lazy-FP handling and then
* return true. If not, emit code to generate an appropriate exception and
* return false.
*/
static bool vfp_access_check_m(DisasContext *s)
{
if (s->fp_excp_el) {
/*
* 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);
return false;
}
/* Handle M-profile lazy FP state mechanics */
/* Trigger lazy-state preservation if necessary */
gen_preserve_fp_state(s);
/* Update ownership of FP context and create new FP context if needed */
gen_update_fp_context(s);
return true;
}
@ -242,7 +251,11 @@ static bool full_vfp_access_check(DisasContext *s, bool ignore_vfp_enabled)
*/
bool vfp_access_check(DisasContext *s)
{
return full_vfp_access_check(s, false);
if (arm_dc_feature(s, ARM_FEATURE_M)) {
return vfp_access_check_m(s);
} else {
return vfp_access_check_a(s, false);
}
}
static bool trans_VSEL(DisasContext *s, arg_VSEL *a)
@ -732,7 +745,11 @@ static bool trans_VMSR_VMRS(DisasContext *s, arg_VMSR_VMRS *a)
return false;
}
if (!full_vfp_access_check(s, ignore_vfp_enabled)) {
/*
* Call vfp_access_check_a() directly, because we need to tell
* it to ignore FPEXC.EN for some register accesses.
*/
if (!vfp_access_check_a(s, ignore_vfp_enabled)) {
return true;
}