From f8afb12a2d7503de6558c23cacd7acbf6e9fe678 Mon Sep 17 00:00:00 2001 From: Jake Hillion Date: Thu, 5 Jun 2025 19:09:26 +0100 Subject: [PATCH] x86/platform/amd: move final timeout check to after final sleep MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit __hsmp_send_message sleeps between result read attempts and has a timeout of 100ms. Under extreme load it's possible for these sleeps to take a long time, exceeding the 100ms. In this case the current code does not check the register and fails with ETIMEDOUT. Refactor the loop to ensure there is at least one read of the register after a sleep of any duration. This removes instances of ETIMEDOUT with a single caller, even with a misbehaving scheduler. Tested on AMD Bergamo machines. Suggested-by: Blaise Sanouillet Reviewed-by: Suma Hegde Tested-by: Suma Hegde Signed-off-by: Jake Hillion Link: https://lore.kernel.org/r/20250605-amd-hsmp-v2-1-a811bc3dd74a@hillion.co.uk Reviewed-by: Ilpo Järvinen Signed-off-by: Ilpo Järvinen --- drivers/platform/x86/amd/hsmp/hsmp.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/drivers/platform/x86/amd/hsmp/hsmp.c b/drivers/platform/x86/amd/hsmp/hsmp.c index 538b36b97095..fa8bd5839dd2 100644 --- a/drivers/platform/x86/amd/hsmp/hsmp.c +++ b/drivers/platform/x86/amd/hsmp/hsmp.c @@ -97,7 +97,7 @@ static int __hsmp_send_message(struct hsmp_socket *sock, struct hsmp_message *ms short_sleep = jiffies + msecs_to_jiffies(HSMP_SHORT_SLEEP); timeout = jiffies + msecs_to_jiffies(HSMP_MSG_TIMEOUT); - while (time_before(jiffies, timeout)) { + while (true) { ret = sock->amd_hsmp_rdwr(sock, mbinfo->msg_resp_off, &mbox_status, HSMP_RD); if (ret) { dev_err(sock->dev, "Error %d reading mailbox status\n", ret); @@ -106,6 +106,10 @@ static int __hsmp_send_message(struct hsmp_socket *sock, struct hsmp_message *ms if (mbox_status != HSMP_STATUS_NOT_READY) break; + + if (!time_before(jiffies, timeout)) + break; + if (time_before(jiffies, short_sleep)) usleep_range(50, 100); else -- 2.39.5