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UPSTREAM: arm64/sme: Save and restore streaming mode over EFI runtime calls

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When saving and restoring the floating point state over an EFI runtime
call ensure that we handle streaming mode, only handling FFR if we are not
in streaming mode and ensuring that we are in normal mode over the call
into runtime services.

We currently assume that ZA will not be modified by runtime services, the
specification is not yet finalised so this may need updating if that
changes.

Signed-off-by: Mark Brown <broonie@kernel.org>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Link: https://lore.kernel.org/r/20220419112247.711548-24-broonie@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
(cherry picked from commit e0838f6373)
Signed-off-by: Will Deacon <willdeacon@google.com>
Bug: 233587962
Bug: 233588291
Change-Id: I9d4d05592424936cbad874b1d243f5b7b06904fb
This commit is contained in:
Mark Brown
2022-04-19 12:22:31 +01:00
committed by Will Deacon
parent 4b54a99d42
commit 91ea5abae0
1 changed files with 42 additions and 6 deletions
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48
arch/arm64/kernel/fpsimd.c
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@@ -1056,21 +1056,25 @@ int vec_verify_vq_map(enum vec_type type)
static void __init sve_efi_setup(void)
{
struct vl_info *info = &vl_info[ARM64_VEC_SVE];
int max_vl = 0;
int i;
if (!IS_ENABLED(CONFIG_EFI))
return;
for (i = 0; i < ARRAY_SIZE(vl_info); i++)
max_vl = max(vl_info[i].max_vl, max_vl);
/*
* alloc_percpu() warns and prints a backtrace if this goes wrong.
* This is evidence of a crippled system and we are returning void,
* so no attempt is made to handle this situation here.
*/
if (!sve_vl_valid(info->max_vl))
if (!sve_vl_valid(max_vl))
goto fail;
efi_sve_state = __alloc_percpu(
SVE_SIG_REGS_SIZE(sve_vq_from_vl(info->max_vl)), SVE_VQ_BYTES);
SVE_SIG_REGS_SIZE(sve_vq_from_vl(max_vl)), SVE_VQ_BYTES);
if (!efi_sve_state)
goto fail;
@@ -1842,6 +1846,7 @@ EXPORT_SYMBOL(kernel_neon_end);
static DEFINE_PER_CPU(struct user_fpsimd_state, efi_fpsimd_state);
static DEFINE_PER_CPU(bool, efi_fpsimd_state_used);
static DEFINE_PER_CPU(bool, efi_sve_state_used);
static DEFINE_PER_CPU(bool, efi_sm_state);
/*
* EFI runtime services support functions
@@ -1876,12 +1881,28 @@ void __efi_fpsimd_begin(void)
*/
if (system_supports_sve() && likely(efi_sve_state)) {
char *sve_state = this_cpu_ptr(efi_sve_state);
bool ffr = true;
u64 svcr;
__this_cpu_write(efi_sve_state_used, true);
if (system_supports_sme()) {
svcr = read_sysreg_s(SYS_SVCR_EL0);
if (!system_supports_fa64())
ffr = svcr & SYS_SVCR_EL0_SM_MASK;
__this_cpu_write(efi_sm_state, ffr);
}
sve_save_state(sve_state + sve_ffr_offset(sve_max_vl()),
&this_cpu_ptr(&efi_fpsimd_state)->fpsr,
true);
ffr);
if (system_supports_sme())
sysreg_clear_set_s(SYS_SVCR_EL0,
SYS_SVCR_EL0_SM_MASK, 0);
} else {
fpsimd_save_state(this_cpu_ptr(&efi_fpsimd_state));
}
@@ -1904,11 +1925,26 @@ void __efi_fpsimd_end(void)
if (system_supports_sve() &&
likely(__this_cpu_read(efi_sve_state_used))) {
char const *sve_state = this_cpu_ptr(efi_sve_state);
bool ffr = true;
/*
* Restore streaming mode; EFI calls are
* normal function calls so should not return in
* streaming mode.
*/
if (system_supports_sme()) {
if (__this_cpu_read(efi_sm_state)) {
sysreg_clear_set_s(SYS_SVCR_EL0,
0,
SYS_SVCR_EL0_SM_MASK);
if (!system_supports_fa64())
ffr = efi_sm_state;
}
}
sve_set_vq(sve_vq_from_vl(sve_get_vl()) - 1);
sve_load_state(sve_state + sve_ffr_offset(sve_max_vl()),
&this_cpu_ptr(&efi_fpsimd_state)->fpsr,
true);
ffr);
__this_cpu_write(efi_sve_state_used, false);
} else {