On 24/05/2022 18:03, Russell King (Oracle) wrote:
On Tue, May 24, 2022 at 03:50:17PM +0100, Jon Hunter wrote:
Hi Ard,
On 28/03/2022 14:47, Ard Biesheuvel wrote:
The Spectre-BHB mitigations were inadvertently left disabled for
Cortex-A15, due to the fact that cpu_v7_bugs_init() is not called in
that case. So fix that.
Signed-off-by: Ard Biesheuvel <ardb@xxxxxxxxxx>
---
arch/arm/mm/proc-v7-bugs.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/arch/arm/mm/proc-v7-bugs.c b/arch/arm/mm/proc-v7-bugs.c
index 06dbfb968182..fb9f3eb6bf48 100644
--- a/arch/arm/mm/proc-v7-bugs.c
+++ b/arch/arm/mm/proc-v7-bugs.c
@@ -288,6 +288,7 @@ void cpu_v7_ca15_ibe(void)
{
if (check_spectre_auxcr(this_cpu_ptr(&spectre_warned), BIT(0)))
cpu_v7_spectre_v2_init();
+ cpu_v7_spectre_bhb_init();
}
void cpu_v7_bugs_init(void)
Since this patch has been merged, I am seeing a ton of messages when booting
Linux on tegra124-jetson-tk1 ...
[ 1233.327547] CPU0: Spectre BHB: using loop workaround
[ 1233.327795] CPU1: Spectre BHB: using loop workaround
[ 1233.328270] CPU1: Spectre BHB: using loop workaround
Now that you mention this, I vaguely remember some email on the list a
while ago about this being caused by something like cpuidle - but I'm
unable to find it now.
[0] https://lore.kernel.org/linux-arm-kernel/20220519161310.1489625-1-dmitry.osipenko@xxxxxxxxxxxxx/T/
That was probably it.
I am seeing ...
[ 4.415167] CPU0: Spectre BHB: using loop workaround
[ 4.417621] [<c01109a0>] (unwind_backtrace) from [<c010b7ac>] (show_stack+0x10/0x14)
[ 4.430291] [<c010b7ac>] (show_stack) from [<c09c2b38>] (dump_stack+0xc0/0xd4)
[ 4.437512] [<c09c2b38>] (dump_stack) from [<c011a6c8>] (cpu_v7_spectre_bhb_init+0xd8/0x190)
[ 4.445943] [<c011a6c8>] (cpu_v7_spectre_bhb_init) from [<c010dee8>] (cpu_suspend+0xac/0xc8)
[ 4.454377] [<c010dee8>] (cpu_suspend) from [<c011e7e4>] (tegra114_idle_power_down+0x74/0x78)
[ 4.462898] [<c011e7e4>] (tegra114_idle_power_down) from [<c06d3b44>] (cpuidle_enter_state+0x130/0x524)
[ 4.472286] [<c06d3b44>] (cpuidle_enter_state) from [<c0164a30>] (do_idle+0x1b0/0x200)
[ 4.480199] [<c0164a30>] (do_idle) from [<c0164d28>] (cpu_startup_entry+0x18/0x1c)
[ 4.487762] [<c0164d28>] (cpu_startup_entry) from [<801018cc>] (0x801018cc)
So definitely CPU idle.
We can't really do this for the other print, because the system status
can change as a result of CPUs being brought online. :(
How about making this a pr_debug as opposed to pr_info?
Jon
--
nvpublic
