On Fri, 08 Apr 2022 21:03:29 +0100,
Kalesh Singh <kaleshsingh@xxxxxxxxxx> wrote:
>
> Reintroduce the __kvm_nvhe_ symbols in kallsyms, ignoring the local
> symbols in this namespace. The local symbols are not informative and
> can cause aliasing issues when symbolizing the addresses.
>
> With the necessary symbols now in kallsyms we can symbolize nVHE
> addresses using the %p print format specifier:
>
> [ 98.916444][ T426] kvm [426]: nVHE hyp panic at: [<ffffffc0096156fc>] __kvm_nvhe_overflow_stack+0x8/0x34!
>
> Signed-off-by: Kalesh Singh <kaleshsingh@xxxxxxxxxx>
> Tested-by: Fuad Tabba <tabba@xxxxxxxxxx>
> Reviewed-by: Fuad Tabba <tabba@xxxxxxxxxx>
> ---
>
> Changes in v6:
> - Add Fuad's Reviewed-by and Tested-by tags.
>
> Changes in v2:
> - Fix printk warnings - %p expects (void *)
>
>
> arch/arm64/kvm/handle_exit.c | 13 +++++--------
> scripts/kallsyms.c | 2 +-
> 2 files changed, 6 insertions(+), 9 deletions(-)
>
> diff --git a/arch/arm64/kvm/handle_exit.c b/arch/arm64/kvm/handle_exit.c
> index 97fe14aab1a3..a377b871bf58 100644
> --- a/arch/arm64/kvm/handle_exit.c
> +++ b/arch/arm64/kvm/handle_exit.c
> @@ -295,13 +295,8 @@ void __noreturn __cold nvhe_hyp_panic_handler(u64 esr, u64 spsr,
> u64 elr_in_kimg = __phys_to_kimg(elr_phys);
> u64 hyp_offset = elr_in_kimg - kaslr_offset() - elr_virt;
> u64 mode = spsr & PSR_MODE_MASK;
> + u64 panic_addr = elr_virt + hyp_offset;
>
> - /*
> - * The nVHE hyp symbols are not included by kallsyms to avoid issues
> - * with aliasing. That means that the symbols cannot be printed with the
> - * "%pS" format specifier, so fall back to the vmlinux address if
> - * there's no better option.
> - */
> if (mode != PSR_MODE_EL2t && mode != PSR_MODE_EL2h) {
> kvm_err("Invalid host exception to nVHE hyp!\n");
> } else if (ESR_ELx_EC(esr) == ESR_ELx_EC_BRK64 &&
> @@ -321,9 +316,11 @@ void __noreturn __cold nvhe_hyp_panic_handler(u64 esr, u64 spsr,
> if (file)
> kvm_err("nVHE hyp BUG at: %s:%u!\n", file, line);
> else
> - kvm_err("nVHE hyp BUG at: %016llx!\n", elr_virt + hyp_offset);
> + kvm_err("nVHE hyp BUG at: [<%016llx>] %pB!\n", panic_addr,
> + (void *)panic_addr);
> } else {
> - kvm_err("nVHE hyp panic at: %016llx!\n", elr_virt + hyp_offset);
> + kvm_err("nVHE hyp panic at: [<%016llx>] %pB!\n", panic_addr,
> + (void *)panic_addr);
> }
>
> /*
> diff --git a/scripts/kallsyms.c b/scripts/kallsyms.c
> index 8caabddf817c..ad2c93640a92 100644
> --- a/scripts/kallsyms.c
> +++ b/scripts/kallsyms.c
> @@ -111,7 +111,7 @@ static bool is_ignored_symbol(const char *name, char type)
> ".L", /* local labels, .LBB,.Ltmpxxx,.L__unnamed_xx,.LASANPC, etc. */
> "__crc_", /* modversions */
> "__efistub_", /* arm64 EFI stub namespace */
> - "__kvm_nvhe_", /* arm64 non-VHE KVM namespace */
> + "__kvm_nvhe_$", /* arm64 local symbols in non-VHE KVM namespace */
> "__AArch64ADRPThunk_", /* arm64 lld */
> "__ARMV5PILongThunk_", /* arm lld */
> "__ARMV7PILongThunk_",
If you are sanitising this, shouldn'tt you also apply the same rules
as the rest of the kernel for non-'__-kvm_nvhe_' symbols? For example,
I see a long list of .L* symbols:
0000000000000000 r __kvm_nvhe_.L144721
0000000000000090 r __kvm_nvhe_.L144721
00000000000000b4 r __kvm_nvhe_.L144721
00000000000004b0 r __kvm_nvhe_.L144721
000000000000051c r __kvm_nvhe_.L144721
0000000000000650 r __kvm_nvhe_.L144721
0000000000000694 r __kvm_nvhe_.L144721
0000000000000761 r __kvm_nvhe_.L144721
00000000000007a7 r __kvm_nvhe_.L144721
00000000000007c7 r __kvm_nvhe_.L144721
0000000000000814 r __kvm_nvhe_.L144721
0000000000000b08 r __kvm_nvhe_.L144721
0000000000003200 r __kvm_nvhe_.L144721
(83 of them in total on a local build) that I think should also be
trimmed.
Thanks,
M.
--
Without deviation from the norm, progress is not possible.
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