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SubjectRe: [PATCH -next] efi/tpm: fix a compilation warning
On Tue, Jun 11, 2019 at 3:59 PM Qian Cai <cai@lca.pw> wrote:
>
> The linux-next "tpm: Reserve the TPM final events table" [1] introduced
> a compilation warning,
>
> drivers/firmware/efi/tpm.c: In function 'efi_tpm_eventlog_init':
> drivers/firmware/efi/tpm.c:80:10: warning: passing argument 1 of
> 'tpm2_calc_event_log_size' makes pointer from integer without a cast
> [-Wint-conversion]
> tbl_size = tpm2_calc_event_log_size(efi.tpm_final_log
> drivers/firmware/efi/tpm.c:19:43: note: expected 'void *' but argument
> is of type 'long unsigned int'
>
> Fix it by making a necessary cast for the argument 1 of
> tpm2_calc_event_log_size().
>
> [1] https://lore.kernel.org/linux-efi/20190520205501.177637-3-matthewgarrett@google.com/
>
> Signed-off-by: Qian Cai <cai@lca.pw>

I see the same build warning, but I don't think adding a cast here
solves the problem:

- efi.tpm_final_log is a physical address that gets passed into
memremap() to return a pointer
- tpm2_calc_event_log_size() takes a pointer argument and
dereferences it.

My best guess is that we should pass the output of memremap()
here rather than the input:

--- a/drivers/firmware/efi/tpm.c
+++ b/drivers/firmware/efi/tpm.c
@@ -75,7 +75,7 @@ int __init efi_tpm_eventlog_init(void)
goto out;
}

- tbl_size = tpm2_calc_event_log_size(efi.tpm_final_log
+ tbl_size = tpm2_calc_event_log_size(final_tbl
+ sizeof(final_tbl->version)
+ sizeof(final_tbl->nr_events),
final_tbl->nr_events,
No idea if that is actually what was intended here, but it makes
the code look more plausible.

Arnd

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