Skip to content

Commit

Permalink
arm64: Add per-cpu infrastructure to call ARCH_WORKAROUND_2
Browse files Browse the repository at this point in the history
In a heterogeneous system, we can end up with both affected and
unaffected CPUs. Let's check their status before calling into the
firmware.

Reviewed-by: Julien Grall <julien.grall@arm.com>
Reviewed-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
  • Loading branch information
Marc Zyngier authored and Catalin Marinas committed May 31, 2018
1 parent 8e29062 commit 5cf9ce6
Show file tree
Hide file tree
Showing 2 changed files with 9 additions and 4 deletions.
2 changes: 2 additions & 0 deletions arch/arm64/kernel/cpu_errata.c
Original file line number Diff line number Diff line change
Expand Up @@ -233,6 +233,8 @@ enable_smccc_arch_workaround_1(const struct arm64_cpu_capabilities *entry)
#endif /* CONFIG_HARDEN_BRANCH_PREDICTOR */

#ifdef CONFIG_ARM64_SSBD
DEFINE_PER_CPU_READ_MOSTLY(u64, arm64_ssbd_callback_required);

void __init arm64_update_smccc_conduit(struct alt_instr *alt,
__le32 *origptr, __le32 *updptr,
int nr_inst)
Expand Down
11 changes: 7 additions & 4 deletions arch/arm64/kernel/entry.S
Original file line number Diff line number Diff line change
Expand Up @@ -140,8 +140,10 @@ alternative_else_nop_endif

// This macro corrupts x0-x3. It is the caller's duty
// to save/restore them if required.
.macro apply_ssbd, state
.macro apply_ssbd, state, targ, tmp1, tmp2
#ifdef CONFIG_ARM64_SSBD
ldr_this_cpu \tmp2, arm64_ssbd_callback_required, \tmp1
cbz \tmp2, \targ
mov w0, #ARM_SMCCC_ARCH_WORKAROUND_2
mov w1, #\state
alternative_cb arm64_update_smccc_conduit
Expand Down Expand Up @@ -176,12 +178,13 @@ alternative_cb_end
ldr x19, [tsk, #TSK_TI_FLAGS] // since we can unmask debug
disable_step_tsk x19, x20 // exceptions when scheduling.

apply_ssbd 1
apply_ssbd 1, 1f, x22, x23

#ifdef CONFIG_ARM64_SSBD
ldp x0, x1, [sp, #16 * 0]
ldp x2, x3, [sp, #16 * 1]
#endif
1:

mov x29, xzr // fp pointed to user-space
.else
Expand Down Expand Up @@ -323,8 +326,8 @@ alternative_if ARM64_WORKAROUND_845719
alternative_else_nop_endif
#endif
3:
apply_ssbd 0

apply_ssbd 0, 5f, x0, x1
5:
.endif

msr elr_el1, x21 // set up the return data
Expand Down

0 comments on commit 5cf9ce6

Please sign in to comment.