Messages in this thread | | | Date | Thu, 28 Apr 2022 11:21:56 +0100 | From | Will Deacon <> | Subject | Re: [PATCH v2] arm64: add the printing of tpidr_elx in __show_regs() |
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On Wed, Mar 16, 2022 at 02:24:08PM +0800, Zhen Lei wrote: > Commit 7158627686f0 ("arm64: percpu: implement optimised pcpu access > using tpidr_el1") and commit 6d99b68933fb ("arm64: alternatives: use > tpidr_el2 on VHE hosts") use tpidr_elx to cache my_cpu_offset to optimize > pcpu access. However, when performing reverse execution based on the > registers and the memory contents in kdump, this information is sometimes > required if there is a pcpu access. > > Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com> > --- > arch/arm64/kernel/process.c | 11 +++++++++++ > 1 file changed, 11 insertions(+) > > v1 --> v2: > Directly print the tpidr_elx register of the current exception level. > Avoid coupling with the implementation of 'my_cpu_offset'. > > diff --git a/arch/arm64/kernel/process.c b/arch/arm64/kernel/process.c > index 5369e649fa79ff8..738932e6fa4e947 100644 > --- a/arch/arm64/kernel/process.c > +++ b/arch/arm64/kernel/process.c > @@ -216,6 +216,17 @@ void __show_regs(struct pt_regs *regs) > show_regs_print_info(KERN_DEFAULT); > print_pstate(regs); > > + switch (read_sysreg(CurrentEL)) {
This should use is_kernel_in_hyp_mode() to detect if we're running at El2.
> + case CurrentEL_EL1: > + printk("tpidr_el1 : %016llx\n", read_sysreg(TPIDR_EL1)); > + break; > + case CurrentEL_EL2: > + printk("tpidr_el2 : %016llx\n", read_sysreg(TPIDR_EL2)); > + break; > + default: > + break; > + }
I think this path can be triggered directly from usermode, so we really shouldn't be printing raw kernel virtual addresses here.
Will
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