[PATCH 07/14] ARM: spectre-v2: add Cortex A8 and A15 validation of the IBE bit
From: geert@linux-m68k.org (Geert Uytterhoeven)
Date: 2018-05-22 10:38:05
Also in:
kvmarm
Hi Russell, On Wed, May 16, 2018 at 1:01 PM, Russell King [off-list ref] wrote:
When the branch predictor hardening is enabled, firmware must have set the IBE bit in the auxiliary control register. If this bit has not been set, the Spectre workarounds will not be functional. Add validation that this bit is set, and print a warning at alert level if this is not the case. Signed-off-by: Russell King <redacted>
Thanks for your patch!
quoted hunk ↗ jump to hunk
--- /dev/null +++ b/arch/arm/mm/proc-v7-bugs.c@@ -0,0 +1,29 @@ +// SPDX-License-Identifier: GPL-2.0 +#include <linux/kernel.h> +#include <linux/smp.h> + +static __maybe_unused void cpu_v7_check_auxcr_set(u32 mask, const char *msg) +{ + u32 aux_cr; + + asm("mrc p15, 0, %0, c1, c0, 1" : "=r" (aux_cr)); + + if ((aux_cr & mask) != mask) + pr_err("CPU%u: %s", smp_processor_id(), msg);
pr_alert(), to match the patch description.
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert at linux-m68k.org
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