[PATCH AUTOSEL 6.18-5.10] tpm: tpm_tis_spi: fix nodef CR50 tpm_tis_spi_resume is null

[PATCH AUTOSEL 6.18-5.10] tpm: tpm_tis_spi: fix nodef CR50 tpm_tis_spi_resume is null

[Sasha Levin]

From: Li Jun <lijun01@kylinos.cn>

[ Upstream commit b4d1adc70471d0752bba674552d19971ed9fa869 ]

if no define CONFIG_TCG_TIS_SPI_CR50 in config,
the add of tpm_tis_spi_resume is null, this cause the tpm chip to
fail to resume.

Signed-off-by: Li Jun <lijun01@kylinos.cn>
Link: https://lore.kernel.org/r/20260812100914.3540149-1-lijun01@kylinos.cn
Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org>
Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---

LLM Generated explanations, may be completely bogus:

Local tree is **6.12.111** (`p-6.12-3-gc504cf0baa3d8`). The SPI TPM
header still defines `tpm_tis_spi_resume` as `NULL` unless CR50 is
built, so this resume bug is present here.

===============================================================
PHASE 1: COMMIT MESSAGE FORENSICS
===============================================================

Step 1.1: PARSE THE SUBJECT LINE
Record: **[tpm / tpm_tis_spi] [fix] CR50 not defined leaves
`tpm_tis_spi_resume` NULL**

Step 1.2: PARSE ALL COMMIT MESSAGE TAGS
Record:
- **Fixes:** none (expected; not a negative signal)
- **Reported-by:** none
- **Tested-by:** none
- **Reviewed-by:** Jarkko Sakkinen `<jarkko@kernel.org>` (TPM
  maintainer)
- **Acked-by:** none
- **Link:** `https://lore.kernel.org/r/20260812100914.3540149-1-
  lijun01@kylinos.cn`
- **Cc: stable:** none (expected)
- **Signed-off-by:** Li Jun `<lijun01@kylinos.cn>` (author); Jarkko
  Sakkinen (maintainer)
- Ignore pipeline-added Sasha Levin SOB / Upstream-commit markers if
  present

Step 1.3: ANALYZE THE COMMIT BODY TEXT
Record:
- **Bug:** Without `CONFIG_TCG_TIS_SPI_CR50`, `tpm_tis_spi_resume` is
  `#define`d to `NULL`.
- **Symptom/failure mode:** SPI TPM chip fails to resume after system
  sleep.
- **Version info:** none in the message.
- **Root cause:** Resume callback is compiled in only for CR50, but
  `SIMPLE_DEV_PM_OPS` in `tpm_tis_spi_main.c` always uses
  `tpm_tis_spi_resume` for every SPI TIS device.

Step 1.4: DETECT HIDDEN BUG FIXES
Record: Not hidden. This is an explicit resume-path bug fix. The wording
is poor English, but the claimed failure is concrete.

===============================================================
PHASE 2: DIFF ANALYSIS - LINE BY LINE
===============================================================

Step 2.1: INVENTORY THE CHANGES
Record:
- **File:** `drivers/char/tpm/tpm_tis_spi.h` only (~+6 / −2)
- **Functions:** none; preprocessor selection of the resume callback
- **Scope:** single-file surgical header change

Step 2.2: UNDERSTAND THE CODE FLOW CHANGE
Record:
- **Before:** `#if CONFIG_PM_SLEEP && CONFIG_TCG_TIS_SPI_CR50` → `extern
  tpm_tis_spi_resume`; else → `#define tpm_tis_spi_resume NULL`.
- **After:**
  - `CONFIG_PM_SLEEP && CR50` → CR50 `tpm_tis_spi_resume` (resets
    `wake_after`, then `tpm_tis_resume`)
  - `CONFIG_PM_SLEEP && !CR50` → `#define tpm_tis_spi_resume
    tpm_tis_resume`
  - `!CONFIG_PM_SLEEP` → still `NULL`
- **Path:** system sleep resume for `tpm_tis_spi`
  (`SIMPLE_DEV_PM_OPS(tpm_tis_pm, tpm_pm_suspend, tpm_tis_spi_resume)`).

Step 2.3: IDENTIFY THE BUG MECHANISM
Record:
- **Category:** logic / PM correctness (missing resume callback)
- **Mechanism:** `tpm_pm_suspend()` sets `TPM_CHIP_FLAG_SUSPENDED`. With
  a NULL `.resume`, that flag is never cleared. `tpm_try_get_ops()` then
  returns `-EIO` (`rc` starts as `-EIO` and the SUSPENDED branch jumps
  to `out_lock` without starting the chip). TPM 1.2 self-test / IRQ re-
  enable in `tpm_tis_resume()` are skipped as well.
- **Fix:** restore the pre-CR50 callback (`tpm_tis_resume`), which
  Infineon/ST/Atmel SPI TIS used before 797c0113c9a48.

Step 2.4: ASSESS THE FIX QUALITY
Record:
- Obviously correct: aliases the existing exported `tpm_tis_resume`
  already used by `tpm_tis.c` and `tpm_tis_i2c.c`.
- `tpm_tis_spi.h` includes `tpm_tis_core.h`, which declares
  `tpm_tis_resume` under `CONFIG_PM_SLEEP` — same gate as the new
  `#define`.
- Nested `#if` indentation is ugly kernel style, not a functional risk.
  Jarkko accepted it as-is.
- **Regression risk:** very low. CR50 path unchanged. Non-CR50 path
  restored to the historical, still-current TIS resume helper.

===============================================================
PHASE 3: GIT HISTORY INVESTIGATION
===============================================================

Step 3.1: BLAME THE CHANGED LINES
Record:
- Introduced by **797c0113c9a48** (`tpm: tpm_tis_spi: Support cr50
  devices`, Andrey Pronin / Stephen Boyd, 2019-11-12).
- `git blame -L 43,47 drivers/char/tpm/tpm_tis_spi.h` attributes the
  `#if ... && CR50` / `#define ... NULL` block entirely to that commit.
- Present since v5.5-era CR50 support; long-lived in this 6.12 tree.

Step 3.2: FOLLOW THE FIXES: TAG
Record: No Fixes: tag. The introducing commit is 797c0113c9a48. `git
merge-base --is-ancestor 797c0113c9a48 HEAD` succeeded — it is in this
tree. Before that commit, `tpm_tis_spi.c` used `SIMPLE_DEV_PM_OPS(...,
tpm_tis_resume)` (verified with `git show
797c0113c9a48^:drivers/char/tpm/tpm_tis_spi.c`).

Step 3.3: CHECK FILE HISTORY FOR RELATED CHANGES
Record:
- `git log --oneline -S tpm_tis_spi_resume -- drivers/char/tpm/` only
  shows 797c0113c9a48. No later rewrite of this symbol in this tree.
- Header history besides that is unrelated (`6422cbd3c52de` phy_ops
  cleanup).
- Standalone; not patch X/Y.

Step 3.4: CHECK THE AUTHOR'S OTHER COMMITS
Record: `git log --author='Li Jun' -- drivers/char/tpm/` is empty in
this tree. Author is an outside contributor. Weight comes from
**Reviewed-by / Signed-off-by Jarkko Sakkinen**, TPM DEVICE DRIVER
maintainer.

Step 3.5: CHECK FOR DEPENDENT/PREREQUISITE COMMITS
Record: None. The `#define` uses `tpm_tis_resume`, present since
**41a5e1cf1fe15** (2016, `tpm/tpm_tis: Split tpm_tis driver into a
core...`). Can apply standalone.

===============================================================
PHASE 4: MAILING LIST AND EXTERNAL RESEARCH
===============================================================

Step 4.1: FIND THE ORIGINAL PATCH DISCUSSION
Record:
- `b4 mbox 20260812100914.3540149-1-lijun01@kylinos.cn` saved a
  2-message thread (lore WebFetch returned 403; b4 succeeded).
- Submission: Li Jun, 12 Aug 2026, `[PATCH] tpm: tpm_tis_spi: fix nodef
  CR50 tpm_tis_spi_resume is null`
- Reply: Jarkko Sakkinen, 21 Aug 2026: **Reviewed-by: Jarkko Sakkinen**
  — no NAK, no requested changes, no extra revisions.
- `b4 dig -a` on the CR50 introducer was attempted; lore search from b4
  returned a server error. Not needed for this candidate (the 2026
  thread was retrieved directly).
- No Cc: stable in the thread.

Step 4.2: CHECK WHO REVIEWED THE PATCH
Record: Recipients were peterhuewe@gmx.de, jarkko@kernel.org,
jgg@ziepe.ca, linux-integrity@vger.kernel.org — the TPM maintainer set.
Jarkko reviewed.

Step 4.3: SEARCH FOR THE BUG REPORT
Record: No syzbot/bugzilla. The report is the patch itself: Kylinos hit
resume failure with CR50 disabled. Severity from author: TPM chip fails
to resume.

Step 4.4: CHECK FOR RELATED PATCHES AND SERIES
Record: Standalone `[PATCH]`, not a series. No follow-up in that thread.

Step 4.5: CHECK STABLE MAILING LIST HISTORY
Record: WebSearch of lore.kernel.org/stable for this subject found no
prior stable discussion. Nothing indicating it was rejected.

===============================================================
PHASE 5: CODE SEMANTIC ANALYSIS
===============================================================

Step 5.1: IDENTIFY KEY FUNCTIONS IN THE DIFF
Record: No function body edited. Symbols involved: `tpm_tis_spi_resume`
(header), used as resume callback; fallback `tpm_tis_resume`.

Step 5.2: TRACE CALLERS
Record:
- Only caller: `drivers/char/tpm/tpm_tis_spi_main.c:310`
  `static SIMPLE_DEV_PM_OPS(tpm_tis_pm, tpm_pm_suspend,
  tpm_tis_spi_resume);`
- Wired as `.pm = &tpm_tis_pm` on `tpm_tis_spi_driver`.
- Invoked by the PM core on system suspend/resume/hibernation
  (`.suspend/.resume/.freeze/.thaw/.poweroff/.restore` via
  `SYSTEM_SLEEP_PM_OPS`).
- Context: process context, PM not IRQ.

Step 5.3: TRACE CALLEES
Record:
- CR50 `tpm_tis_spi_resume`: reset `phy->wake_after = jiffies`, then
  `tpm_tis_resume(dev)`.
- `tpm_tis_resume`: `tpm_chip_start` → optional IRQ re-enable → TPM 1.2
  `tpm1_do_selftest` → `tpm_chip_stop` → `tpm_pm_resume` (clears
  `TPM_CHIP_FLAG_SUSPENDED`).
- Generic fallback after this patch is exactly `tpm_tis_resume`.

Step 5.4: FOLLOW THE CALL CHAIN
Record: Userspace/system suspend (`echo mem > /sys/power/state`, systemd
suspend, etc.) → PM core → `tpm_pm_suspend` (always registered) → later
resume callback. Reachable on any board with `CONFIG_TCG_TIS_SPI` +
`CONFIG_PM_SLEEP` and no CR50. After the broken resume, `/dev/tpm0`,
hwrng, and key operations fail via `tpm_try_get_ops()` → `-EIO`.

Step 5.5: SEARCH FOR SIMILAR PATTERNS
Record: Sibling TIS phys already use `tpm_tis_resume` (`tpm_tis.c:249`,
`tpm_tis_i2c.c:322`, `tpm_tis_synquacer.c:110`). Only SPI TIS lost that
callback when CR50 was optional. The header already stubs
`cr50_spi_probe` with `-ENODEV` when CR50 is off; resume was not stubbed
equivalently.

===============================================================
PHASE 6: CROSS-REFERENCING AGAINST THE LOCAL TREE
===============================================================

Step 6.1: DOES THE BUGGY CODE EXIST IN THIS TREE?
Record: **Yes.** `drivers/char/tpm/tpm_tis_spi.h:43-47` is the exact
pre-patch `#if defined(CONFIG_PM_SLEEP) &&
defined(CONFIG_TCG_TIS_SPI_CR50)` / `#define tpm_tis_spi_resume NULL`
block. Bug since 797c0113c9a48 (2019). Candidate is **not** already in
this tree (`git log --grep='fix nodef CR50'` / `'tpm_tis_spi_resume is
null'` empty).

Step 6.2: CHECK FOR BACKPORT COMPLICATIONS
Record: **Clean apply.** Current header matches the patch’s old side. No
later refactor of this `#ifdef` in 6.12.

Step 6.3: CHECK IF RELATED FIXES ARE ALREADY HERE
Record: No alternate resume fix. Recent TPM SPI change here is unrelated
(`bb63a0530e8e6` wait_woken).

===============================================================
PHASE 7: SUBSYSTEM AND MAINTAINER CONTEXT
===============================================================

Step 7.1: IDENTIFY THE SUBSYSTEM AND ITS CRITICALITY
Record: **TPM character driver** (`drivers/char/tpm/`). **IMPORTANT** —
not core mm/VFS, but security hardware used for measured boot, keys,
hwrng. SPI TIS is the usual driver for discrete TPMs on embedded boards
(SLB9670, ST33HTPM, ATTPM20P).

Step 7.2: ASSESS SUBSYSTEM ACTIVITY
Record: Actively maintained (many 6.12 TPM stable-style fixes). The
buggy `#ifdef` itself has been untouched since 2019.

===============================================================
PHASE 8: IMPACT AND RISK ASSESSMENT
===============================================================

Step 8.1: DETERMINE WHO IS AFFECTED
Record: **Driver-specific / config-specific.** Users with
`CONFIG_TCG_TIS_SPI=y/m`, `CONFIG_PM_SLEEP=y`, and
**`CONFIG_TCG_TIS_SPI_CR50` unset** (Kconfig bool, default n).
Chromebooks with CR50 enabled are unaffected. Infineon/ST/Atmel SPI TPM
boards (common on ARM/embedded) are the hit.

Step 8.2: DETERMINE THE TRIGGER CONDITIONS
Record: Any system sleep/hibernation of that SPI TPM. Common on
laptops/SBCs that suspend. Unprivileged users typically cannot suspend;
after resume, any user of `/dev/tpm0` sees failures. Not a race.

Step 8.3: DETERMINE THE FAILURE MODE SEVERITY
Record:
- **Failure mode:** TPM stays `TPM_CHIP_FLAG_SUSPENDED`; ops return
  `-EIO`. Device does not come back after suspend. TPM 1.2 also skips
  resume self-test.
- **Severity: HIGH** (device dead after suspend; security hardware). Not
  a panic, but a hard functional break of the TPM until reboot.

Step 8.4: CALCULATE RISK-BENEFIT RATIO
Record:
- **Benefit: high** for SPI TPM + suspend without CR50 — restores post-
  resume TPM.
- **Risk: very low** — 6-line header, CR50 path unchanged, fallback is
  the same function other TIS drivers already use.
- **Ratio:** strongly favors backport.

===============================================================
PHASE 9: FINAL SYNTHESIS
===============================================================

Step 9.1: COMPILE THE EVIDENCE
FOR:
- Real user-visible bug: SPI TPM does not resume unless CR50 is compiled
  in.
- Regression vs pre-2019 `tpm_tis_resume` usage, introduced by optional
  CR50 support.
- Bug and introducing commit are in this 6.12 tree.
- Tiny, obviously correct, applies cleanly.
- TPM maintainer Reviewed-by.
- Failure is `-EIO` on all TPM ops after suspend (verified in
  `tpm_try_get_ops`).

AGAINST:
- Commit message is terse / no Fixes:/stable tags (not a reason to
  reject).
- Nested `#if` style is non-idiomatic (no runtime risk).
- Not a crash/UAF; “only” a device that stays unusable after suspend.
- Affects a subset of TPM users (SPI, no CR50).

UNRESOLVED:
- Could not WebFetch lore (403); thread was recovered with `b4 mbox`.
- No independent bugzilla/syzbot report.

Step 9.2: APPLY THE STABLE RULES CHECKLIST
1. Obviously correct and tested? **PASS** — alias to existing helper;
   maintainer reviewed.
2. Fixes a real bug that affects users? **PASS** — author reports TPM
   resume failure; code confirms NULL resume + sticky SUSPENDED.
3. Important issue? **PASS** — HIGH: TPM unusable after suspend
   (security device / `-EIO` on all ops).
4. Small and contained? **PASS** — one header, ~6 lines.
5. No new features or APIs? **PASS**.
6. Can apply to the local tree? **PASS** — exact match, no prereqs.

Step 9.3: CHECK FOR EXCEPTION CATEGORIES
Record: Not an ID/quirk/DT/build/docs exception. Ordinary small bugfix.

Step 9.4: MAKE YOUR DECISION
This belongs in 6.12. The driver suspends the TPM, then installs a NULL
resume whenever CR50 is off, so the chip never leaves
`TPM_CHIP_FLAG_SUSPENDED`. The patch restores `tpm_tis_resume` for that
config, which is what this driver used before CR50 and what sibling TIS
drivers still use.

**What it solves for stable users:** After suspend, SPI TPMs (SLB9670
and similar) work again without requiring `CONFIG_TCG_TIS_SPI_CR50`.

**Rules:** Small, correct, real functional/security-device bug, no new
API, clean apply.

**Risk vs benefit:** Very low risk, high benefit for the affected
config.

**Concerns:** None that block backport. Style of nested `#if` is
cosmetic.

Verification:
- [Phase 1] Tags: Reviewed-by Jarkko Sakkinen; Link lore Message-ID
  20260812100914.3540149-1-lijun01@kylinos.cn; no Fixes/Reported-
  by/Cc:stable
- [Phase 2] Diff: `tpm_tis_spi.h` only; `#define tpm_tis_spi_resume
  tpm_tis_resume` when PM_SLEEP && !CR50
- [Phase 2] `tpm_tis_spi_main.c:310` `SIMPLE_DEV_PM_OPS(...,
  tpm_tis_spi_resume)` verified
- [Phase 2] `tpm_try_get_ops()` returns `-EIO` if
  `TPM_CHIP_FLAG_SUSPENDED` (`tpm-chip.c:159-174`)
- [Phase 2] `tpm_pm_suspend` sets that flag;
  `tpm_pm_resume`/`tpm_tis_resume` clear it
- [Phase 3] blame: 797c0113c9a48 (2019); `git merge-base --is-ancestor`
  confirms it is in this tree
- [Phase 3] pre-CR50 file used `tpm_tis_resume` in SIMPLE_DEV_PM_OPS
- [Phase 3] candidate not in this tree (`git log --grep` empty)
- [Phase 4] b4 mbox: 2-message thread; Jarkko Reviewed-by; no NAK
- [Phase 4] lore WebFetch 403 — UNVERIFIED via HTTP, recovered via b4
- [Phase 4] no stable-list discussion found
- [Phase 5] callers: only tpm_tis_spi PM ops; siblings already use
  tpm_tis_resume
- [Phase 6] `git describe HEAD` → p-6.12-3-gc504cf0baa3d8; `make
  kernelversion` → 6.12.111; buggy `#ifdef` present; patch old-side
  matches
- [Phase 7] TPM DEVICE DRIVER, maintainer Jarkko
- [Phase 8] Failure: TPM dead after suspend (`-EIO`), severity HIGH;
  risk very low
- UNVERIFIED: whether linus/master already contains a later stylistic
  rewrite of this header (GitHub search snippet still showed the old
  `#ifdef`; does not affect this 6.12 checkout)

**YES**

 drivers/char/tpm/tpm_tis_spi.h | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/drivers/char/tpm/tpm_tis_spi.h b/drivers/char/tpm/tpm_tis_spi.h
index d0f66f6f19318..ced416ecd92c2 100644
--- a/drivers/char/tpm/tpm_tis_spi.h
+++ b/drivers/char/tpm/tpm_tis_spi.h
@@ -40,8 +40,12 @@ static inline int cr50_spi_probe(struct spi_device *spi)
 }
 #endif
 
-#if defined(CONFIG_PM_SLEEP) && defined(CONFIG_TCG_TIS_SPI_CR50)
-extern int tpm_tis_spi_resume(struct device *dev);
+#if defined(CONFIG_PM_SLEEP)
+	#if defined(CONFIG_TCG_TIS_SPI_CR50)
+		extern int tpm_tis_spi_resume(struct device *dev);
+	#else
+		#define  tpm_tis_spi_resume tpm_tis_resume
+	#endif
 #else
 #define tpm_tis_spi_resume	NULL
 #endif
-- 
2.53.0

[PATCH AUTOSEL 6.18] tpm: atmel: depend on X86

[Sasha Levin]

From: Karl Mehltretter <kmehltretter@gmail.com>

[ Upstream commit 4bfacee94f309346bef0b598ea091088b9150af9 ]

tpm_atmel probes for the chip at fixed x86 Super-I/O ports (0x4e) with
inb()/outb(), so it only works on x86. TCG_ATMEL nevertheless depends
only on HAS_IOPORT_MAP/HAS_IOPORT, which arm and arm64 also satisfy.
There the probe is useless, and on platforms whose unbacked I/O access
faults it oopses in init_atmel() at boot (e.g. arm/versatile):

  Unable to handle kernel paging request at virtual address fee0004e
  PC is at init_atmel+0x34/0x244

TCG_NSC and TCG_TIS already "depends on X86" (commit 2f592f2a7d74 ("TPM:
NSC and TIS drivers X86 dependency fix")); TCG_ATMEL was missed. Add the
same dependency.

Signed-off-by: Karl Mehltretter <kmehltretter@gmail.com>
Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org>
Link: https://lore.kernel.org/r/20260712183234.23125-1-kmehltretter@gmail.com
Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---

LLM Generated explanations, may be completely bogus:

## Phase 1: Commit message forensics

**Step 1.1 — Subject**
Record: `[tpm / TCG_ATMEL]` `[depend]` Restrict the Atmel TPM driver to
x86 because it probes Super-I/O ports.

**Step 1.2 — Tags**
Record:
- `Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org>` (TPM maintainer)
- `Link: https://lore.kernel.org/r/20260712183234.23125-1-
  kmehltretter@gmail.com`
- `Signed-off-by: Karl Mehltretter` (author)
- `Signed-off-by: Jarkko Sakkinen` (maintainer)
- No `Fixes:`, no `Reported-by:`, no `Cc: stable` (absence is expected
  for this review)
- Ignore any pipeline `Signed-off-by: Sasha Levin` / `[Upstream commit
  …]` markers

**Step 1.3 — Body**
Record:
- Bug: `tpm_atmel` probes Super-I/O at `0x4e` with `inb()`/`outb()`.
  Kconfig only required `HAS_IOPORT_MAP`/`HAS_IOPORT`, which ARM/arm64
  also satisfy.
- Symptom: boot oops, `Unable to handle kernel paging request at virtual
  address fee0004e`, `PC is at init_atmel+0x34/0x244` (example:
  arm/versatile).
- Root cause: unbacked PCI I/O window access on non-x86.
- Same class of fix as `2f592f2a7d74` (`TCG_NSC` / `TCG_TIS` `depends on
  X86`); `TCG_ATMEL` was missed.

**Step 1.4 — Hidden bug fix?**
Record: Not hidden. Explicit crash fix via Kconfig dependency. Not
cleanup or a new feature.

## Phase 2: Diff analysis

**Step 2.1 — Inventory**
Record: One file, `drivers/char/tpm/Kconfig`. `TCG_ATMEL`: replace
`depends on HAS_IOPORT_MAP` + `depends on HAS_IOPORT` with `depends on
X86`. Scope: single-file, two-line Kconfig change.

**Step 2.2 — Code flow**
Record: Before: any arch with I/O-port mapping can build/enable
`tpm_atmel`; `init_atmel()` always probes `0x4e`. After: the driver is
not built on non-x86. Affected path: module/builtin init, not a hot
path.

**Step 2.3 — Bug mechanism**
Record: Kconfig/hardware-scope bug that produces a NULL/unmapped I/O
dereference. On ARM, `inb(0x4e)` becomes a load at
`PCI_IO_VIRT_BASE+0x4e` (`0xfee0004e`). If that page is not mapped, the
kernel oopses.

**Step 2.4 — Fix quality**
Record: Obviously correct for the Super-I/O probe. Minimal. No runtime
locking/API change. Regression risk is only over-restricting platforms
that still have a working non-x86 path. That matters on **this** tree
(see Phase 6): PPC64 OF support is still present, so the backport must
be `depends on X86 || PPC64`, not bare `depends on X86`.

## Phase 3: Git history

**Step 3.1 — Blame**
Record: `TCG_ATMEL` dates to `1da177e4c3f41` (Linux 2.6.12-rc2). Local
depends lines:
- `depends on PPC64 || HAS_IOPORT_MAP` — `ce816fa88cca0` (2014; rename
  of `HAS_IOPORT` → `HAS_IOPORT_MAP`)
- `depends on HAS_IOPORT` — `6155153601183` (“char: tpm: handle
  HAS_IOPORT dependencies”, 2024; **in this tree**)

The Super-I/O probe in `tpm_atmel.h` (`#else` of `CONFIG_PPC64`) has
been there for the life of the driver.

**Step 3.2 — Fixes: tag**
Record: None. Related historical commit `2f592f2a7d74` (2011, **in this
tree**) added `depends on X86` for NSC/TIS after PPC oopses; Atmel was
not included.

**Step 3.3 — Related file history**
Record: `5578b4347bb5d` (“tpm: atmel: Drop PPC64 specific MMIO setup”,
2024-11-22) is **not** an ancestor of this checkout (`git merge-base
--is-ancestor` exit 1). It is an ancestor of the candidate. That commit
changed Kconfig to `depends on HAS_IOPORT_MAP` only; the candidate then
changed that to `depends on X86`.

**Step 3.4 — Author**
Record: Karl Mehltretter — this is the only Atmel TPM commit from that
author on `origin/master`. Jarkko Sakkinen (TPM maintainer) reviewed and
applied it.

**Step 3.5 — Prerequisites**
Record: The **verbatim** diff assumes PPC64 was already dropped. That
drop is not in 6.12. The **semantic** fix does not need that drop: this
tree can use `depends on X86 || PPC64` and keep the existing OF path.
Standalone with that one-line adaptation. Do not pull in `5578b4347bb5d`
(feature removal, ~140 lines).

## Phase 4: Mailing list / external

**Step 4.1 — Original discussion**
Record: `b4 dig -c 4bfacee94f309` →
https://patch.msgid.link/20260712183234.23125-1-kmehltretter@gmail.com
`b4 dig -a`: single revision (v1 only).
Thread (mbox): author patch + Jarkko `Reviewed-by`. No NAK, no stable
debate, no risk flags.

**Step 4.2 — Recipients** (`b4 dig -w`)
Record: Jarkko Sakkinen, Peter Huewe, Jason Gunthorpe, `linux-
integrity`, `linux-kernel`. Right maintainers/list.

**Step 4.3 — Bug report**
Record: No syzbot/bugzilla. Concrete oops in the commit message; PC and
fault address match ARM `inb(0x4e)`.

**Step 4.4 — Series**
Record: Standalone, not patch x/y.

**Step 4.5 — Stable list**
Record: No stable-specific thread found. lore.kernel.org HTTP fetch
returned 403; discussion recovered via `b4 dig -m`. UNVERIFIED: whether
anyone later nominated it on `stable@`.

## Phase 5: Semantic / call surface

**Step 5.1 — Functions**
Record: No C functions changed. Runtime path gated: `init_atmel()` →
`atmel_get_base_addr()` → `atmel_verify_tpm11()` → `tpm_read_index()` →
`outb`/`inb` at `TPM_ADDR` (`0x4E` in `drivers/char/tpm/tpm.h`).

**Step 5.2 — Callers**
Record: `module_init(init_atmel)` — builtin boot or `modprobe
tpm_atmel`.

**Step 5.3 — Callees**
Record: Super-I/O index/data ports; no allocation/locking in the
faulting probe.

**Step 5.4 — Reachability**
Record: Yes, if `CONFIG_TCG_ATMEL=y/m`. Not a syscall. User/config must
enable an x86 Super-I/O TPM driver.
`arch/parisc/configs/generic-64bit_defconfig` sets `CONFIG_TCG_ATMEL=m`.
ARM `allyesconfig`/custom configs can set it `=y` and oops at boot.

**Step 5.5 — Similar patterns**
Record: `TCG_NSC` already `depends on X86` in this tree. `TCG_TIS` is
`depends on X86 || OF` here (OF added later; not Super-I/O).

## Phase 6: This checkout (6.12.y)

**Step 6.1 — Does the buggy code exist?**
Record: Yes.
- Tree: `git describe` → `p-6.12-3-gc504cf0baa3d8`, `make kernelversion`
  → **6.12.111**
- Candidate `4bfacee94f309` is **not** in HEAD
- Local Kconfig:

```164:171:drivers/char/tpm/Kconfig
config TCG_ATMEL
        tristate "Atmel TPM Interface"
        depends on PPC64 || HAS_IOPORT_MAP
        depends on HAS_IOPORT
```

- Non-PPC64 `tpm_atmel.h` still does Super-I/O `inb`/`outb` at
  `TPM_ADDR`.
- `arch/arm/Kconfig` `select HAS_IOPORT`. `HAS_IOPORT_MAP` defaults y
  unless `NO_IOPORT_MAP`. `ARCH_VERSATILE` does **not** select
  `NO_IOPORT_MAP`.
- ARM `PCI_IO_VIRT_BASE` is `0xfee00000`; `inb(0x4e)` → `0xfee0004e`,
  matching the oops.

**Step 6.2 — Backport difficulty**
Record: Exact hunk will not apply (this tree still has `PPC64 ||
HAS_IOPORT_MAP`). Trivial adaptation:

```
depends on X86 || PPC64
```

Do **not** apply bare `depends on X86`; that would disable the still-
present PPC64 OF path (`CONFIG_PPC64` in `tpm_atmel.h`).

**Step 6.3 — Related fixes already here?**
Record: No other Atmel X86-dependency fix. `2f592f2a7d74` only covered
NSC/TIS.

## Phase 7: Subsystem context

**Step 7.1**
Record: `drivers/char/tpm` — TPM. Criticality: **IMPORTANT** for TPM
users; Atmel Super-I/O is a legacy path. Still a driver that can be
built into generic/distro kernels.

**Step 7.2**
Record: TPM core is active (HMAC, new backends). `tpm_atmel` itself is
mature/legacy.

## Phase 8: Impact and risk

**Step 8.1 — Who is affected**
Record: Config-specific: `CONFIG_TCG_ATMEL` on non-x86 (ARM/arm64 with
PCI I/O, parisc defconfig, etc.). Not all 6.12 users.

**Step 8.2 — Trigger**
Record: Boot if builtin; module load if `=m`. Unprivileged users cannot
trigger unless the module is loaded. Commonness: low on production ARM,
high on `allyesconfig` / mistaken enablement. Author hit it on
versatile.

**Step 8.3 — Failure mode**
Record: Kernel paging-request oops in `init_atmel`. Severity:
**CRITICAL** when the driver is enabled (boot crash if `=y`).

**Step 8.4 — Risk/benefit**
Record:
- Benefit: stops a real oops; Kconfig-only.
- Risk: very low if PPC64 is preserved; **high if applied verbatim**
  (would hide `tpm_atmel` on PPC64 while the OF code remains).
- Ratio: favorable **with** `X86 || PPC64`.

## Phase 9: Synthesis

**Evidence FOR**
- Documented boot oops; fault address verified against ARM `inb()`.
- Same bug class already fixed for NSC/TIS in this tree.
- One-file Kconfig change; TPM maintainer Reviewed-by.
- Buggy probe is in this 6.12 tree.
- Fits “build/Kconfig dependency” stable exception; prevents a crash,
  adds no API.

**Evidence AGAINST**
- Verbatim patch does not apply; depends on PPC64-drop `5578b4347bb5d`
  which is **not** in 6.12.
- `TCG_ATMEL` is not in ARM defconfigs; impact is config-selected.
- Bare `depends on X86` would be a PPC64 regression on this tree.

**Unresolved**
- UNVERIFIED: whether any live PPC64 machine still uses AT97SC3201 via
  OF (Rob Herring later found no in-tree powerpc configs; that drop is
  still not in 6.12, so this backport should keep PPC64).
- UNVERIFIED: stable@ discussion (lore HTTP 403).

**Stable rules**
1. Obviously correct and tested? **PASS** (Kconfig restrict + maintainer
   review; oops matches code).
2. Real user-visible bug? **PASS** (boot oops).
3. Important (crash)? **PASS** when the option is enabled.
4. Small and contained? **PASS** (1–2 Kconfig lines).
5. No new features/APIs? **PASS**.
6. Apply to this tree? **PASS with backport** (`depends on X86 ||
   PPC64`); **FAIL** if taken verbatim.

**Exception category:** Kconfig/build dependency fix that prevents a
crash.

The 6.12 bug is real: `TCG_ATMEL` can still be enabled on
ARM/arm64/parisc, and `init_atmel()` will touch `0x4e` and oops on
unbacked I/O. Restricting the symbol is the right stable fix. Use
`depends on X86 || PPC64` so the still-present PowerPC OF path is not
dropped.

Verification:
- [Phase 1] Tags: Reviewed-by Jarkko; lore Link; no Fixes/Cc:stable
- [Phase 2] Diff: Kconfig only, `HAS_IOPORT*` → `X86`
- [Phase 3] `git describe` / `make kernelversion`: 6.12.111
- [Phase 3] `git merge-base --is-ancestor 4bfacee94f309 HEAD`: not in
  tree
- [Phase 3] `git merge-base --is-ancestor 5578b4347bb5d HEAD`: PPC64
  drop not in tree
- [Phase 3] `git merge-base --is-ancestor 2f592f2a7d74 HEAD`: NSC/TIS
  X86 dep is in tree
- [Phase 3] `git blame drivers/char/tpm/Kconfig`: HAS_IOPORT added by
  `6155153601183`
- [Phase 4] `b4 dig -c 4bfacee94f309`: v1 only; Jarkko Reviewed-by; no
  NAK
- [Phase 4] lore WebFetch: 403; thread read from `b4 dig -m`
- [Phase 5] `init_atmel` → `atmel_verify_tpm11` →
  `tpm_read_index(TPM_ADDR=0x4E)`
- [Phase 6] Local Kconfig still `PPC64 || HAS_IOPORT_MAP`; ARM
  `PCI_IO_VIRT_BASE=0xfee00000` matches oops
- [Phase 6] `ARCH_VERSATILE` does not select `NO_IOPORT_MAP`;
  `HAS_IOPORT` selected by ARM
- [Phase 8] parisc `generic-64bit_defconfig` has `CONFIG_TCG_ATMEL=m`
- UNVERIFIED: live PPC64 Atmel hardware; stable@ thread beyond b4 mbox

**YES**

 drivers/char/tpm/Kconfig | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/char/tpm/Kconfig b/drivers/char/tpm/Kconfig
index 8a8f692b60880..5f672f2c01b04 100644
--- a/drivers/char/tpm/Kconfig
+++ b/drivers/char/tpm/Kconfig
@@ -163,8 +163,7 @@ config TCG_NSC
 
 config TCG_ATMEL
 	tristate "Atmel TPM Interface"
-	depends on HAS_IOPORT_MAP
-	depends on HAS_IOPORT
+	depends on X86
 	help
 	  If you have a TPM security chip from Atmel say Yes and it 
 	  will be accessible from within Linux.  To compile this driver 
-- 
2.53.0