diff options
| author | Marc Zyngier <maz@kernel.org> | 2020-07-31 19:38:23 +0200 |
|---|---|---|
| committer | Catalin Marinas <catalin.marinas@arm.com> | 2020-08-21 12:39:56 +0200 |
| commit | d49f7d7376d0c0daf8680984a37bd07581ac7d38 (patch) | |
| tree | 393b2ffb2e6cf8f7594a37955a15e60571238f33 /arch/arm64/kernel/entry.S | |
| parent | Linux 5.9-rc1 (diff) | |
| download | linux-d49f7d7376d0c0daf8680984a37bd07581ac7d38.tar.xz linux-d49f7d7376d0c0daf8680984a37bd07581ac7d38.zip | |
arm64: Move handling of erratum 1418040 into C code
Instead of dealing with erratum 1418040 on each entry and exit,
let's move the handling to __switch_to() instead, which has
several advantages:
- It can be applied when it matters (switching between 32 and 64
bit tasks).
- It is written in C (yay!)
- It can rely on static keys rather than alternatives
Signed-off-by: Marc Zyngier <maz@kernel.org>
Tested-by: Sai Prakash Ranjan <saiprakash.ranjan@codeaurora.org>
Reviewed-by: Stephen Boyd <swboyd@chromium.org>
Acked-by: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20200731173824.107480-2-maz@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Diffstat (limited to 'arch/arm64/kernel/entry.S')
| -rw-r--r-- | arch/arm64/kernel/entry.S | 21 |
1 files changed, 0 insertions, 21 deletions
diff --git a/arch/arm64/kernel/entry.S b/arch/arm64/kernel/entry.S index 2646178c8329..55af8b504b65 100644 --- a/arch/arm64/kernel/entry.S +++ b/arch/arm64/kernel/entry.S @@ -170,19 +170,6 @@ alternative_cb_end stp x28, x29, [sp, #16 * 14] .if \el == 0 - .if \regsize == 32 - /* - * If we're returning from a 32-bit task on a system affected by - * 1418040 then re-enable userspace access to the virtual counter. - */ -#ifdef CONFIG_ARM64_ERRATUM_1418040 -alternative_if ARM64_WORKAROUND_1418040 - mrs x0, cntkctl_el1 - orr x0, x0, #2 // ARCH_TIMER_USR_VCT_ACCESS_EN - msr cntkctl_el1, x0 -alternative_else_nop_endif -#endif - .endif clear_gp_regs mrs x21, sp_el0 ldr_this_cpu tsk, __entry_task, x20 @@ -294,14 +281,6 @@ alternative_else_nop_endif tst x22, #PSR_MODE32_BIT // native task? b.eq 3f -#ifdef CONFIG_ARM64_ERRATUM_1418040 -alternative_if ARM64_WORKAROUND_1418040 - mrs x0, cntkctl_el1 - bic x0, x0, #2 // ARCH_TIMER_USR_VCT_ACCESS_EN - msr cntkctl_el1, x0 -alternative_else_nop_endif -#endif - #ifdef CONFIG_ARM64_ERRATUM_845719 alternative_if ARM64_WORKAROUND_845719 #ifdef CONFIG_PID_IN_CONTEXTIDR |