Re: [PATCH v2 2/4] soc: apple: rtkit: Implement OSLog buffers properly

Alyssa Rosenzweig
2025-02-26T19:07:21Z

Le Wed , Feb 26, 2025 at 07:00:04PM +0000, Sven Peter via B4 Relay a écrit :
> From: Hector Martin <marcan@marcan.st>
>
> Apparently nobody can figure out where the old logic came from, but it
> seems like it has never been actually used on any supported firmware to
> this day. OSLog buffers were apparently never requested.
>
> But starting with 13.3, we actually need this implemented properly for
> MTP (and later AOP) to work, so let's actually do that.
>
> Signed-off-by: Hector Martin <marcan@marcan.st>
> Signed-off-by: Sven Peter <sven@svenpeter.dev>
> ---
> drivers/soc/apple/rtkit-internal.h | 1 +
> drivers/soc/apple/rtkit.c | 56 +++++++++++++++++++++++---------------
> 2 files changed, 35 insertions(+), 22 deletions(-)
>
> diff --git a/drivers/soc/apple/rtkit-internal.h b/drivers/soc/apple/rtkit-internal.h
> index 27c9fa745fd5..b8d5244678f0 100644
> --- a/drivers/soc/apple/rtkit-internal.h
> +++ b/drivers/soc/apple/rtkit-internal.h
> @@ -44,6 +44,7 @@ struct apple_rtkit {
>
> struct apple_rtkit_shmem ioreport_buffer;
> struct apple_rtkit_shmem crashlog_buffer;
> + struct apple_rtkit_shmem oslog_buffer;
>
> struct apple_rtkit_shmem syslog_buffer;
> char *syslog_msg_buffer;
> diff --git a/drivers/soc/apple/rtkit.c b/drivers/soc/apple/rtkit.c
> index be0d08861168..7e7b4f64ab17 100644
> --- a/drivers/soc/apple/rtkit.c
> +++ b/drivers/soc/apple/rtkit.c
> @@ -67,8 +67,9 @@ enum {
> #define APPLE_RTKIT_SYSLOG_MSG_SIZE GENMASK_ULL(31, 24)
>
> #define APPLE_RTKIT_OSLOG_TYPE GENMASK_ULL(63, 56)
> -#define APPLE_RTKIT_OSLOG_INIT 1
> -#define APPLE_RTKIT_OSLOG_ACK 3
> +#define APPLE_RTKIT_OSLOG_BUFFER_REQUEST 1
> +#define APPLE_RTKIT_OSLOG_SIZE GENMASK_ULL(55, 36)
> +#define APPLE_RTKIT_OSLOG_IOVA GENMASK_ULL(35, 0)
>
> #define APPLE_RTKIT_MIN_SUPPORTED_VERSION 11
> #define APPLE_RTKIT_MAX_SUPPORTED_VERSION 12
> @@ -259,15 +260,21 @@ static int apple_rtkit_common_rx_get_buffer(struct apple_rtkit *rtk,
> struct apple_rtkit_shmem *buffer,
> u8 ep, u64 msg)
> {
> - size_t n_4kpages = FIELD_GET(APPLE_RTKIT_BUFFER_REQUEST_SIZE, msg);
> u64 reply;
> int err;
>
> + /* The different size vs. IOVA shifts look odd but are indeed correct this way */
> + if (ep == APPLE_RTKIT_EP_OSLOG) {
> + buffer->size = FIELD_GET(APPLE_RTKIT_OSLOG_SIZE, msg);
> + buffer->iova = FIELD_GET(APPLE_RTKIT_OSLOG_IOVA, msg) << 12;
> + } else {
> + buffer->size = FIELD_GET(APPLE_RTKIT_BUFFER_REQUEST_SIZE, msg) << 12;
> + buffer->iova = FIELD_GET(APPLE_RTKIT_BUFFER_REQUEST_IOVA, msg);
> + }
> +
> buffer->buffer = NULL;
> buffer->iomem = NULL;
> buffer->is_mapped = false;
> - buffer->iova = FIELD_GET(APPLE_RTKIT_BUFFER_REQUEST_IOVA, msg);
> - buffer->size = n_4kpages << 12;
>
> dev_dbg(rtk->dev, "RTKit: buffer request for 0x%zx bytes at %pad\n",
> buffer->size, &buffer->iova);
> @@ -292,11 +299,21 @@ static int apple_rtkit_common_rx_get_buffer(struct apple_rtkit *rtk,
> }
>
> if (!buffer->is_mapped) {
> - reply = FIELD_PREP(APPLE_RTKIT_SYSLOG_TYPE,
> - APPLE_RTKIT_BUFFER_REQUEST);
> - reply |= FIELD_PREP(APPLE_RTKIT_BUFFER_REQUEST_SIZE, n_4kpages);
> - reply |= FIELD_PREP(APPLE_RTKIT_BUFFER_REQUEST_IOVA,
> - buffer->iova);
> + /* oslog uses different fields and needs a shifted IOVA instead of size */
> + if (ep == APPLE_RTKIT_EP_OSLOG) {
> + reply = FIELD_PREP(APPLE_RTKIT_OSLOG_TYPE,
> + APPLE_RTKIT_OSLOG_BUFFER_REQUEST);
> + reply |= FIELD_PREP(APPLE_RTKIT_OSLOG_SIZE, buffer->size);
> + reply |= FIELD_PREP(APPLE_RTKIT_OSLOG_IOVA,
> + buffer->iova >> 12);
> + } else {
> + reply = FIELD_PREP(APPLE_RTKIT_SYSLOG_TYPE,
> + APPLE_RTKIT_BUFFER_REQUEST);
> + reply |= FIELD_PREP(APPLE_RTKIT_BUFFER_REQUEST_SIZE,
> + buffer->size >> 12);
> + reply |= FIELD_PREP(APPLE_RTKIT_BUFFER_REQUEST_IOVA,
> + buffer->iova);
> + }
> apple_rtkit_send_message(rtk, ep, reply, NULL, false);
> }
>
> @@ -494,25 +511,18 @@ static void apple_rtkit_syslog_rx(struct apple_rtkit *rtk, u64 msg)
> }
> }
>
> -static void apple_rtkit_oslog_rx_init(struct apple_rtkit *rtk, u64 msg)
> -{
> - u64 ack;
> -
> - dev_dbg(rtk->dev, "RTKit: oslog init: msg: 0x%llx\n", msg);
> - ack = FIELD_PREP(APPLE_RTKIT_OSLOG_TYPE, APPLE_RTKIT_OSLOG_ACK);
> - apple_rtkit_send_message(rtk, APPLE_RTKIT_EP_OSLOG, ack, NULL, false);
> -}
> -
> static void apple_rtkit_oslog_rx(struct apple_rtkit *rtk, u64 msg)
> {
> u8 type = FIELD_GET(APPLE_RTKIT_OSLOG_TYPE, msg);
>
> switch (type) {
> - case APPLE_RTKIT_OSLOG_INIT:
> - apple_rtkit_oslog_rx_init(rtk, msg);
> + case APPLE_RTKIT_OSLOG_BUFFER_REQUEST:
> + apple_rtkit_common_rx_get_buffer(rtk, &rtk->oslog_buffer,
> + APPLE_RTKIT_EP_OSLOG, msg);
> break;
> default:
> - dev_warn(rtk->dev, "RTKit: Unknown oslog message: %llx\n", msg);
> + dev_warn(rtk->dev, "RTKit: Unknown oslog message: %llx\n",
> + msg);
> }
> }
>
> @@ -729,6 +739,7 @@ int apple_rtkit_reinit(struct apple_rtkit *rtk)
>
> apple_rtkit_free_buffer(rtk, &rtk->ioreport_buffer);
> apple_rtkit_free_buffer(rtk, &rtk->crashlog_buffer);
> + apple_rtkit_free_buffer(rtk, &rtk->oslog_buffer);
> apple_rtkit_free_buffer(rtk, &rtk->syslog_buffer);
>
> kfree(rtk->syslog_msg_buffer);
> @@ -916,6 +927,7 @@ void apple_rtkit_free(struct apple_rtkit *rtk)
>
> apple_rtkit_free_buffer(rtk, &rtk->ioreport_buffer);
> apple_rtkit_free_buffer(rtk, &rtk->crashlog_buffer);
> + apple_rtkit_free_buffer(rtk, &rtk->oslog_buffer);
> apple_rtkit_free_buffer(rtk, &rtk->syslog_buffer);
>
> kfree(rtk->syslog_msg_buffer);
>
> --
> 2.34.1
>
>