On Fri, Dec 19, 2025 at 9:44 PM Heinrich Schuchardt <[email protected]> wrote: > > On 12/17/25 11:39, Ilias Apalodimas wrote: > > Thanks Patrick, > > > > On Wed, 17 Dec 2025 at 09:26, Patrick Rudolph > > <[email protected]> wrote: > >> > >> When FTRACE is enabled the EFI runtime will call the tracing functions > >> that are not marked as __efi_runtime and cause a kernel panic since > >> the functions have been previously unmapped by the kernel. > >> > >> Resolve this issue by adding the 'notrace' attribute to '__efi_runtime' > >> attribute and thus disable tracing the EFI runtime. If required this > >> can be worked out latter. > > What is the point of actually booting with a U-Boot binary with FTRACE > enabled? All your trace data will be lost. > > Wouldn't it be preferable to error out at ExitBootServices() and > retrieve the trace? > > The current implementation of FTRACE looks flawed. The trace buffer > should be allocated from LMB so that it cannot overwrite images or EFI data. > Hi Heinrich, I'm not that familiar with the tracing yet. My expectation was that the trace buffer is marked as reserved and could be retrieved from /dev/mem, however that's not the case. I updated the CONFIG_BOOTCOMMAND to write the trace file to disk before it runs "bootflow scan" as described in the documentation. I can then retrieve the trace data from disk. That works for me.
Regards, Patrick Rudolph > Best regards > > Heinrich > > >> > > > > So I agree with this. Fixing is just a matter of moving the missing > > functions to the runtime section, but I don;t think it's worth it, > > unless someone *really* wants to instrument runtime calls. > > OTOH runtime calls in the OS are rare and very limited > > > > Reviewed-by: Ilias Apalodimas <[email protected]> > > > > > >> TEST=Can boot a UEFI compatible linux OS on qemu-q35 when U-Boot was > >> built with FTRACE=1. > >> > >> Signed-off-by: Patrick Rudolph <[email protected]> > >> --- > >> include/efi_loader.h | 2 +- > >> 1 file changed, 1 insertion(+), 1 deletion(-) > >> > >> diff --git a/include/efi_loader.h b/include/efi_loader.h > >> index 3e70ac07055..7a13c390cbe 100644 > >> --- a/include/efi_loader.h > >> +++ b/include/efi_loader.h > >> @@ -66,7 +66,7 @@ struct bootflow; > >> * > >> * static __efi_runtime compute_my_table(void); > >> */ > >> -#define __efi_runtime __section(".text.efi_runtime") > >> +#define __efi_runtime __section(".text.efi_runtime") notrace > >> > >> /* > >> * Call this with mmio_ptr as the _pointer_ to a pointer to an MMIO > >> region > >> -- > >> 2.52.0 > >> >
