[PATCH] platform/x86/intel/pmc: Fix ioremap of bad address

[PATCH] platform/x86/intel/pmc: Fix ioremap of bad address

[David E. Box]

In pmc_core_ssram_get_pmc(), the physical addresses for hidden SSRAM
devices are retrieved from the MMIO region of the primary SSRAM device. If
additional devices are not present, the address returned is zero.
Currently, the code does not check for this condition, resulting in ioremap
incorrectly attempting to map address 0. Add a check for a zero address and
return 0 if no additional devices are found, as it is not an error for the
device to be absent.

Signed-off-by: David E. Box <david.e.box@linux.intel.com>
Fixes: a01486dc4bb1 ("platform/x86/intel/pmc: Cleanup SSRAM discovery")
---
 drivers/platform/x86/intel/pmc/core_ssram.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/platform/x86/intel/pmc/core_ssram.c b/drivers/platform/x86/intel/pmc/core_ssram.c
index 50ebfd586d3f..739569803017 100644
--- a/drivers/platform/x86/intel/pmc/core_ssram.c
+++ b/drivers/platform/x86/intel/pmc/core_ssram.c
@@ -269,8 +269,12 @@ pmc_core_ssram_get_pmc(struct pmc_dev *pmcdev, int pmc_idx, u32 offset)
 		/*
 		 * The secondary PMC BARS (which are behind hidden PCI devices)
 		 * are read from fixed offsets in MMIO of the primary PMC BAR.
+		 * If a device is not present, the value will be 0.
 		 */
 		ssram_base = get_base(tmp_ssram, offset);
+		if (!ssram_base)
+			return 0;
+
 		ssram = ioremap(ssram_base, SSRAM_HDR_SIZE);
 		if (!ssram)
 			return -ENOMEM;

base-commit: 6b228cfc52a6e9b7149cf51e247076963d6561cd
-- 
2.43.0

Re: [PATCH] platform/x86/intel/pmc: Fix ioremap of bad address

[Ilpo Järvinen]

On Mon, 06 Jan 2025 09:46:52 -0800, David E. Box wrote:

> In pmc_core_ssram_get_pmc(), the physical addresses for hidden SSRAM
> devices are retrieved from the MMIO region of the primary SSRAM device. If
> additional devices are not present, the address returned is zero.
> Currently, the code does not check for this condition, resulting in ioremap
> incorrectly attempting to map address 0. Add a check for a zero address and
> return 0 if no additional devices are found, as it is not an error for the
> device to be absent.
> 
> [...]


Thank you for your contribution, it has been applied to my local
review-ilpo-fixes branch. Note it will show up in the public
platform-drivers-x86/review-ilpo-fixes branch only once I've pushed my
local branch there, which might take a while.

The list of commits applied:
[1/1] platform/x86/intel/pmc: Fix ioremap of bad address
      commit: 1d7461d0c8330689117286169106af6531a747ed

--
 i.