2024-02-27 14:06:11

by Armin Wolf

Subject: [PATCH 1/2] platform/x86/amd/pmf: Do not use readl() for policy buffer access

The policy buffer is allocated using normal memory allocation
functions, so readl() should not be used on it.

Compile-tested only.

Signed-off-by: Armin Wolf <[email protected]>
---
drivers/platform/x86/amd/pmf/tee-if.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/platform/x86/amd/pmf/tee-if.c b/drivers/platform/x86/amd/pmf/tee-if.c
index 16973bebf55f..70d09103ab18 100644
--- a/drivers/platform/x86/amd/pmf/tee-if.c
+++ b/drivers/platform/x86/amd/pmf/tee-if.c
@@ -249,8 +249,8 @@ static int amd_pmf_start_policy_engine(struct amd_pmf_dev *dev)
u32 cookie, length;
int res;

- cookie = readl(dev->policy_buf + POLICY_COOKIE_OFFSET);
- length = readl(dev->policy_buf + POLICY_COOKIE_LEN);
+ cookie = dev->policy_buf[POLICY_COOKIE_OFFSET];
+ length = dev->policy_buf[POLICY_COOKIE_LEN];

if (cookie != POLICY_SIGN_COOKIE || !length)
return -EINVAL;
--
2.39.2

2024-02-27 14:09:55

by Ilpo Järvinen

Subject: Re: [PATCH 1/2] platform/x86/amd/pmf: Do not use readl() for policy buffer access

On Tue, 27 Feb 2024, Armin Wolf wrote:

> The policy buffer is allocated using normal memory allocation
> functions, so readl() should not be used on it.
>
> Compile-tested only.
>
> Signed-off-by: Armin Wolf <[email protected]>
> ---
> drivers/platform/x86/amd/pmf/tee-if.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/platform/x86/amd/pmf/tee-if.c b/drivers/platform/x86/amd/pmf/tee-if.c
> index 16973bebf55f..70d09103ab18 100644
> --- a/drivers/platform/x86/amd/pmf/tee-if.c
> +++ b/drivers/platform/x86/amd/pmf/tee-if.c
> @@ -249,8 +249,8 @@ static int amd_pmf_start_policy_engine(struct amd_pmf_dev *dev)
> u32 cookie, length;
> int res;
>
> - cookie = readl(dev->policy_buf + POLICY_COOKIE_OFFSET);
> - length = readl(dev->policy_buf + POLICY_COOKIE_LEN);
> + cookie = dev->policy_buf[POLICY_COOKIE_OFFSET];
> + length = dev->policy_buf[POLICY_COOKIE_LEN];

Hmm, the next question is, is it okay to get just 8 bits instead the full
dword (the policy_buf is unsigned char *)?

--
i.