Re: [PATCH v6 10/18] ACPI / APEI: preparatory split of ghes->estatus

Borislav Petkov
2018-10-12T16:38:03Z

Nitpick:

Subject: Re: [PATCH v6 10/18] ACPI / APEI: preparatory split of ghes->estatus

Pls have an active formulation in your Subject and start it with a capital
letter, i.e., something like:

"Split ghes->estatus in preparation for... "

On Fri, Sep 21, 2018 at 11:16:57PM +0100, James Morse wrote:
> The NMI-like notifications scribble over ghes->estatus, before
> copying it somewhere else. If this interrupts the ghes_probe() code
> calling ghes_proc() on each struct ghes, the data is corrupted.
>
> We want the NMI-like notifications to use a queued estatus entry

Pls formulate commit messages in passive voice.

> from the beginning. To that end, break up any use of "ghes->estatus"
> so that all functions take the estatus as an argument.
>
> This patch is just moving code around, no change in behaviour.
>
> Signed-off-by: James Morse <james.morse@arm.com>
> ---
> drivers/acpi/apei/ghes.c | 82 ++++++++++++++++++++++------------------
> 1 file changed, 45 insertions(+), 37 deletions(-)
>
> diff --git a/drivers/acpi/apei/ghes.c b/drivers/acpi/apei/ghes.c
> index adf7fd402813..586689cbc0fd 100644
> --- a/drivers/acpi/apei/ghes.c
> +++ b/drivers/acpi/apei/ghes.c
> @@ -298,7 +298,9 @@ static void ghes_copy_tofrom_phys(void *buffer, u64 paddr, u32 len,
> }
> }
>
> -static int ghes_read_estatus(struct ghes *ghes, int silent, int fixmap_idx)
> +static int ghes_read_estatus(struct ghes *ghes,
> + struct acpi_hest_generic_status *estatus,

acpi_hest_generic_status - geez, could this name have been any longer ?!

> + int silent, int fixmap_idx)
> {
> struct acpi_hest_generic *g = ghes->generic;
> u64 buf_paddr;
> @@ -316,26 +318,26 @@ static int ghes_read_estatus(struct ghes *ghes, int silent, int fixmap_idx)
> if (!buf_paddr)
> return -ENOENT;
>
> - ghes_copy_tofrom_phys(ghes->estatus, buf_paddr,
> - sizeof(*ghes->estatus), 1, fixmap_idx);
> - if (!ghes->estatus->block_status)
> + ghes_copy_tofrom_phys(estatus, buf_paddr,
> + sizeof(*estatus), 1, fixmap_idx);

Yeah, let that line stick out - it is easier to follow the code this
way.

> + if (!estatus->block_status)
> return -ENOENT;
>
> ghes->buffer_paddr = buf_paddr;
> ghes->flags |= GHES_TO_CLEAR;
>
> rc = -EIO;
> - len = cper_estatus_len(ghes->estatus);
> - if (len < sizeof(*ghes->estatus))
> + len = cper_estatus_len(estatus);
> + if (len < sizeof(*estatus))
> goto err_read_block;
> if (len > ghes->generic->error_block_length)
> goto err_read_block;
> - if (cper_estatus_check_header(ghes->estatus))
> + if (cper_estatus_check_header(estatus))
> goto err_read_block;
> - ghes_copy_tofrom_phys(ghes->estatus + 1,
> - buf_paddr + sizeof(*ghes->estatus),
> - len - sizeof(*ghes->estatus), 1, fixmap_idx);
> - if (cper_estatus_check(ghes->estatus))
> + ghes_copy_tofrom_phys(estatus + 1,
> + buf_paddr + sizeof(*estatus),
> + len - sizeof(*estatus), 1, fixmap_idx);
> + if (cper_estatus_check(estatus))
> goto err_read_block;
> rc = 0;
>
> @@ -346,13 +348,15 @@ static int ghes_read_estatus(struct ghes *ghes, int silent, int fixmap_idx)
> return rc;
> }
>
> -static void ghes_clear_estatus(struct ghes *ghes, int fixmap_idx)
> +static void ghes_clear_estatus(struct ghes *ghes,
> + struct acpi_hest_generic_status *estatus,
> + int fixmap_idx)
> {
> - ghes->estatus->block_status = 0;
> + estatus->block_status = 0;
> if (!(ghes->flags & GHES_TO_CLEAR))
> return;

<---- newline here.

> - ghes_copy_tofrom_phys(ghes->estatus, ghes->buffer_paddr,
> - sizeof(ghes->estatus->block_status), 0, fixmap_idx);
> + ghes_copy_tofrom_phys(estatus, ghes->buffer_paddr,
> + sizeof(estatus->block_status), 0, fixmap_idx);
> ghes->flags &= ~GHES_TO_CLEAR;
> }
>
> @@ -518,9 +522,10 @@ static int ghes_print_estatus(const char *pfx,
> return 0;
> }
>
> -static void __ghes_panic(struct ghes *ghes)
> +static void __ghes_panic(struct ghes *ghes,
> + struct acpi_hest_generic_status *estatus)

Yeah, let that one stick out too. That struct naming needs slimming.

> {
> - __ghes_print_estatus(KERN_EMERG, ghes->generic, ghes->estatus);
> + __ghes_print_estatus(KERN_EMERG, ghes->generic, estatus);
>
> /* reboot to log the error! */
> if (!panic_timeout)

--
Regards/Gruss,
Boris.

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