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platform/x86/amd/pmc: Only expose stb_read after telemetry buffer is mapped

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amd_stb_s2d_init() creates the v2 "stb_read" debugfs node before mapping
the telemetry buffer into dev->stb_virt_addr, leaving a window during probe
where a read faults on a NULL dev->stb_virt_addr in
amd_stb_debugfs_open_v2()/amd_stb_handle_efr().

This becomes trivial to hit once a failed STB init no longer aborts probe
(next patch), which leaves the node registered with a NULL buffer.  Create
it only after dev->stb_virt_addr is mapped.

Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
Link: https://patch.msgid.link/20260721181756.143084-5-mario.limonciello@amd.com
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
This commit is contained in:
Mario Limonciello 2026-07-21 13:17:54 -05:00 committed by Ilpo Järvinen
parent 0225c1d637
commit 34d145254c
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GPG Key ID: 59AC4F6153E5CE31
1 changed files with 12 additions and 5 deletions
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17
drivers/platform/x86/amd/pmc/mp1_stb.c
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@ -299,10 +299,7 @@ int amd_stb_s2d_init(struct amd_pmc_dev *dev)
if (!enable_stb)
return 0;
if (amd_is_stb_supported(dev)) {
debugfs_create_file("stb_read", 0644, dev->dbgfs_dir, dev,
&amd_stb_debugfs_fops_v2);
} else {
if (!amd_is_stb_supported(dev)) {
debugfs_create_file("stb_read", 0644, dev->dbgfs_dir, dev,
&amd_stb_debugfs_fops);
return 0;
@ -342,8 +339,18 @@ int amd_stb_s2d_init(struct amd_pmc_dev *dev)
}
dev->stb_virt_addr = devm_ioremap(dev->dev, stb_phys_addr, dev->dram_size);
if (!dev->stb_virt_addr)
if (!dev->stb_virt_addr) {
ret = -ENOMEM;
goto out;
}
/*
* Only expose stb_read once the buffer is mapped; otherwise a read
* faults on a NULL dev->stb_virt_addr, now that a failed STB init no
* longer aborts probe.
*/
debugfs_create_file("stb_read", 0644, dev->dbgfs_dir, dev,
&amd_stb_debugfs_fops_v2);
out:
/* Restore the default message port for subsequent SMU operations */