[PATCH v2 0/9] docs: kernel-parameters: Remove ten entries for parameters that no longer exist

[PATCH v2 0/9] docs: kernel-parameters: Remove ten entries for parameters that no longer exist

[Karl Mehltretter]

kernel-parameters.txt still documents ten boot parameters whose parsing
code was removed with the drivers or platforms that used them, one of
them (atarimouse=) since before the git history. One patch per
parameter, each with a Fixes: tag for the commit that removed the
parser, so the maintainers of that area are on their own patch only;
the two pata_legacy module parameters share the last one. Each entry
was checked with git grep for its __setup(), early_param() and
module_param() handler and with git log -S for the removing commit.

Changes in v2:
- patch 9: drop the Fixes: tag for 0dcd0a76370a, which removed the
  separate pata_qdi driver and not the pata_legacy parameter; both
  parameters went away in 3c4d783f6922 alone
- collect the Reviewed-by and Acked-by tags from v1

v1: https://lore.kernel.org/all/20260905070347.25902-1-kmehltretter@gmail.com/

Karl Mehltretter (9):
  docs: kernel-parameters: Drop the atarimouse= entry
  docs: kernel-parameters: Drop the bau= entry
  docs: kernel-parameters: Drop the edac_report= entry
  docs: kernel-parameters: Drop the enable_timer_pin_1 entry
  docs: kernel-parameters: Drop the mini2440= entry
  docs: kernel-parameters: Drop the nomfgpt entry
  docs: kernel-parameters: Drop the omap_mux= entry
  docs: kernel-parameters: Drop the pcmv= entry
  docs: kernel-parameters: Drop the pata_legacy.qdi and
    pata_legacy.winbond entries

 .../admin-guide/kernel-parameters.txt         | 67 -------------------
 1 file changed, 67 deletions(-)

-- 
2.53.0

[PATCH v2 1/9] docs: kernel-parameters: Drop the atarimouse= entry

[Karl Mehltretter]

Nothing in the tree parses atarimouse=. drivers/input/mouse/atarimouse.c
only takes a module parameter, and git log -S finds no __setup() for the
boot parameter anywhere in the git history, so the entry has been stale
since before it.

Drop the entry.

Found by cross-checking every documented name against the __setup(),
early_param() and core_param() registrations in the tree.

Assisted-by: LLM
Signed-off-by: Karl Mehltretter <kmehltretter@gmail.com>
Reviewed-by: Michael Schmitz <schmitzmic@gmail.com>
---
 Documentation/admin-guide/kernel-parameters.txt | 2 --
 1 file changed, 2 deletions(-)

diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index 68647ff4bdd2..c8d96de4c00d 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -591,8 +591,6 @@ Kernel parameters
 
 	ataflop=	[HW,M68k]
 
-	atarimouse=	[HW,MOUSE] Atari Mouse
-
 	atkbd.extra=	[HW] Enable extra LEDs and keys on IBM RapidAccess,
 			EzKey and similar keyboards
 
-- 
2.53.0

[PATCH v2 2/9] docs: kernel-parameters: Drop the bau= entry

[Karl Mehltretter]

bau= went away with commit 39297dde7390 ("x86/platform/uv: Remove UV
BAU TLB Shootdown Handler"); nothing parses it any more.

Drop the entry.

Found by cross-checking every documented name against the __setup(),
early_param() and core_param() registrations in the tree.

Fixes: 39297dde7390 ("x86/platform/uv: Remove UV BAU TLB Shootdown Handler")
Assisted-by: LLM
Signed-off-by: Karl Mehltretter <kmehltretter@gmail.com>
---
 Documentation/admin-guide/kernel-parameters.txt | 7 -------
 1 file changed, 7 deletions(-)

diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index c8d96de4c00d..99d5bb68968a 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -624,13 +624,6 @@ Kernel parameters
 			Format: <int> (must be >=0)
 			Default: 64
 
-	bau=		[X86_UV] Enable the BAU on SGI UV.  The default
-			behavior is to disable the BAU (i.e. bau=0).
-			Format: { "0" | "1" }
-			0 - Disable the BAU.
-			1 - Enable the BAU.
-			unset - Disable the BAU.
-
 	bdev_allow_write_mounted=
 			Format: <bool>
 			Control the ability to open a mounted block device
-- 
2.53.0

[PATCH v2 3/9] docs: kernel-parameters: Drop the edac_report= entry

[Karl Mehltretter]

edac_report= went away with commit fee27d7d9788 ("EDAC: Delete
edac_stub.c"); nothing parses it any more.

Drop the entry.

Found by cross-checking every documented name against the __setup(),
early_param() and core_param() registrations in the tree.

Fixes: fee27d7d9788 ("EDAC: Delete edac_stub.c")
Assisted-by: LLM
Signed-off-by: Karl Mehltretter <kmehltretter@gmail.com>
---
 Documentation/admin-guide/kernel-parameters.txt | 8 --------
 1 file changed, 8 deletions(-)

diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index 99d5bb68968a..2a8d862ef30f 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -1578,14 +1578,6 @@ Kernel parameters
 			PCI device even when its classcode is not of the
 			UART class.
 
-	edac_report=	[HW,EDAC] Control how to report EDAC event
-			Format: {"on" | "off" | "force"}
-			on: enable EDAC to report H/W event. May be overridden
-			by other higher priority error reporting module.
-			off: disable H/W event reporting through EDAC.
-			force: enforce the use of EDAC to report H/W event.
-			default: on.
-
 	edd=		[EDD]
 			Format: {"off" | "on" | "skip[mbr]"}
 
-- 
2.53.0

Re: [PATCH v2 3/9] docs: kernel-parameters: Drop the edac_report= entry

[Borislav Petkov]

On Sat, Sep 05, 2026 at 11:46:43AM +0200, Karl Mehltretter wrote:
> edac_report= went away with commit fee27d7d9788 ("EDAC: Delete
> edac_stub.c"); nothing parses it any more.

Nope, it was:

7fc0b9b995f2 ("EDAC: Drop the EDAC report status checks")

> Drop the entry.
> 
> Found by cross-checking every documented name against the __setup(),
> early_param() and core_param() registrations in the tree.

If you look at fee27d7d9788, you'd read:

    Move the remaining functionality to edac_mc.c. Convert "edac_report=" to
    a module parameter.

-- 
Regards/Gruss,
    Boris.

https://people.kernel.org/tglx/notes-about-netiquette

Re: [PATCH v2 3/9] docs: kernel-parameters: Drop the edac_report= entry

[Karl Mehltretter]

On Sat, Sep 05, 2026 at 08:13:45AM +0100, Borislav Petkov wrote:
> On Sat, Sep 05, 2026 at 11:46:43AM +0200, Karl Mehltretter wrote:
> > edac_report= went away with commit fee27d7d9788 ("EDAC: Delete
> > edac_stub.c"); nothing parses it any more.
> 
> Nope, it was:
> 
> 7fc0b9b995f2 ("EDAC: Drop the EDAC report status checks")
> 

Good catch! I will send a v3.

Thanks,
Karl

Re: [PATCH v2 3/9] docs: kernel-parameters: Drop the edac_report= entry

[Borislav Petkov]

On Sat, Sep 05, 2026 at 05:22:33PM +0200, Karl Mehltretter wrote:
> Good catch! I will send a v3.

Just don't send it immediately but wait a couple of days to gather review
feedback first.

-- 
Regards/Gruss,
    Boris.

https://people.kernel.org/tglx/notes-about-netiquette

[PATCH v2 4/9] docs: kernel-parameters: Drop the enable_timer_pin_1 entry

[Karl Mehltretter]

enable_timer_pin_1 lost its early_param() in commit efa2559f6516 ("x86:
order variables in io_apic_xx.c"); nothing parses it any more.

Drop the entry.

Found by cross-checking every documented name against the __setup(),
early_param() and core_param() registrations in the tree.

Fixes: efa2559f6516 ("x86: order variables in io_apic_xx.c")
Assisted-by: LLM
Signed-off-by: Karl Mehltretter <kmehltretter@gmail.com>
---
 Documentation/admin-guide/kernel-parameters.txt | 6 ------
 1 file changed, 6 deletions(-)

diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index 2a8d862ef30f..f4314492953d 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -1647,12 +1647,6 @@ Kernel parameters
 			to discrete, to make X server driver able to add WB
 			entry later. This parameter enables that.
 
-	enable_timer_pin_1 [X86]
-			Enable PIN 1 of APIC timer
-			Can be useful to work around chipset bugs
-			(in particular on some ATI chipsets).
-			The kernel tries to set a reasonable default.
-
 	enforcing=	[SELINUX] Set initial enforcing status.
 			Format: {"0" | "1"}
 			See security/selinux/Kconfig help text.
-- 
2.53.0

[PATCH v2 5/9] docs: kernel-parameters: Drop the mini2440= entry

[Karl Mehltretter]

mini2440= went away with commit 61b7f8920b17 ("ARM: s3c: remove all
s3c24xx support"); nothing parses it any more.

Drop the entry.

Found by cross-checking every documented name against the __setup(),
early_param() and core_param() registrations in the tree.

Fixes: 61b7f8920b17 ("ARM: s3c: remove all s3c24xx support")
Assisted-by: LLM
Signed-off-by: Karl Mehltretter <kmehltretter@gmail.com>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@oss.qualcomm.com>
---
 .../admin-guide/kernel-parameters.txt         | 21 -------------------
 1 file changed, 21 deletions(-)

diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index f4314492953d..2ed1e2c03c61 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -4052,27 +4052,6 @@ Kernel parameters
 			Enable or disable the microcode minimal revision
 			enforcement for the runtime microcode loader.
 
-	mini2440=	[ARM,HW,KNL]
-			Format:[0..2][b][c][t]
-			Default: "0tb"
-			MINI2440 configuration specification:
-			0 - The attached screen is the 3.5" TFT
-			1 - The attached screen is the 7" TFT
-			2 - The VGA Shield is attached (1024x768)
-			Leaving out the screen size parameter will not load
-			the TFT driver, and the framebuffer will be left
-			unconfigured.
-			b - Enable backlight. The TFT backlight pin will be
-			linked to the kernel VESA blanking code and a GPIO
-			LED. This parameter is not necessary when using the
-			VGA shield.
-			c - Enable the s3c camera interface.
-			t - Reserved for enabling touchscreen support. The
-			touchscreen support is not enabled in the mainstream
-			kernel as of 2.6.30, a preliminary port can be found
-			in the "bleeding edge" mini2440 support kernel at
-			https://repo.or.cz/w/linux-2.6/mini2440.git
-
 	mitigations=
 			[X86,PPC,S390,ARM64,EARLY] Control optional mitigations for
 			CPU vulnerabilities.  This is a set of curated,
-- 
2.53.0

[PATCH v2 6/9] docs: kernel-parameters: Drop the nomfgpt entry

[Karl Mehltretter]

nomfgpt went away with commit c95d1e53ed89 ("cs5535: drop the
Geode-specific MFGPT/GPIO code"); nothing parses it any more.

Drop the entry.

Found by cross-checking every documented name against the __setup(),
early_param() and core_param() registrations in the tree.

Fixes: c95d1e53ed89 ("cs5535: drop the Geode-specific MFGPT/GPIO code")
Assisted-by: LLM
Signed-off-by: Karl Mehltretter <kmehltretter@gmail.com>
---
 Documentation/admin-guide/kernel-parameters.txt | 3 ---
 1 file changed, 3 deletions(-)

diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index 2ed1e2c03c61..d44728a45506 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -4553,9 +4553,6 @@ Kernel parameters
 
 	nomce		[X86-32] Disable Machine Check Exception
 
-	nomfgpt		[X86-32] Disable Multi-Function General Purpose
-			Timer usage (for AMD Geode machines).
-
 	nomodeset	Disable kernel modesetting. Most systems' firmware
 			sets up a display mode and provides framebuffer memory
 			for output. With nomodeset, DRM and fbdev drivers will
-- 
2.53.0

[PATCH v2 7/9] docs: kernel-parameters: Drop the omap_mux= entry

[Karl Mehltretter]

omap_mux= went away with commit e9f5f1e45608 ("ARM: OMAP2+: Remove
legacy mux code"); nothing parses it any more.

Drop the entry.

Found by cross-checking every documented name against the __setup(),
early_param() and core_param() registrations in the tree.

Fixes: e9f5f1e45608 ("ARM: OMAP2+: Remove legacy mux code")
Assisted-by: LLM
Signed-off-by: Karl Mehltretter <kmehltretter@gmail.com>
Reviewed-by: Andreas Kemnade <andreas@kemnade.info>
---
 Documentation/admin-guide/kernel-parameters.txt | 5 -----
 1 file changed, 5 deletions(-)

diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index d44728a45506..48dd273eaf6c 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -4765,11 +4765,6 @@ Kernel parameters
 			waiting for the ACK, so if this is set too high
 			interrupts *may* be lost!
 
-	omap_mux=	[OMAP] Override bootloader pin multiplexing.
-			Format: <mux_mode0.mode_name=value>...
-			For example, to override I2C bus2:
-			omap_mux=i2c2_scl.i2c2_scl=0x100,i2c2_sda.i2c2_sda=0x100
-
 	onenand.bdry=	[HW,MTD] Flex-OneNAND Boundary Configuration
 
 			Format: [die0_boundary][,die0_lock][,die1_boundary][,die1_lock]
-- 
2.53.0

[PATCH v2 8/9] docs: kernel-parameters: Drop the pcmv= entry

[Karl Mehltretter]

pcmv= went away with commit 7aeffbf2ddec ("pcmcia: remove unused
pxa/sa1100 drivers"); nothing parses it any more.

Drop the entry.

Found by cross-checking every documented name against the __setup(),
early_param() and core_param() registrations in the tree.

Fixes: 7aeffbf2ddec ("pcmcia: remove unused pxa/sa1100 drivers")
Assisted-by: LLM
Signed-off-by: Karl Mehltretter <kmehltretter@gmail.com>
---
 Documentation/admin-guide/kernel-parameters.txt | 2 --
 1 file changed, 2 deletions(-)

diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index 48dd273eaf6c..4864e37005be 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -5311,8 +5311,6 @@ Kernel parameters
 		nomsi	Do not use MSI for native PCIe PME signaling (this makes
 			all PCIe root ports use INTx for all services).
 
-	pcmv=		[HW,PCMCIA] BadgePAD 4
-
 	pd_ignore_unused
 			[PM]
 			Keep all power-domains already enabled by bootloader on,
-- 
2.53.0

[PATCH v2 9/9] docs: kernel-parameters: Drop the pata_legacy.qdi and pata_legacy.winbond entries

[Karl Mehltretter]

pata_legacy no longer has the qdi and winbond module parameters:
commit 3c4d783f6922 ("ata: pata_legacy: remove VLB support") removed
both together with the VLB controller support. The entries also refer
to CONFIG_PATA_QDI_MODULE and CONFIG_PATA_WINBOND_VLB_MODULE, which do
not exist either.

Drop both entries.

Fixes: 3c4d783f6922 ("ata: pata_legacy: remove VLB support")
Assisted-by: LLM
Signed-off-by: Karl Mehltretter <kmehltretter@gmail.com>
Acked-by: Damien Le Moal <dlemoal@kernel.org>
---
 Documentation/admin-guide/kernel-parameters.txt | 13 -------------
 1 file changed, 13 deletions(-)

diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index 4864e37005be..33298da28b55 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -4994,19 +4994,6 @@ Kernel parameters
 			the first port in the list above (0x1f0), and so on.
 			By default all supported ports are probed.
 
-	pata_legacy.qdi=	[HW,LIBATA]
-			Format: <int>
-			Set to non-zero to probe QDI controllers.  By default
-			set to 1 if CONFIG_PATA_QDI_MODULE, 0 otherwise.
-
-	pata_legacy.winbond=	[HW,LIBATA]
-			Format: <int>
-			Set to non-zero to probe Winbond controllers.  Use
-			the standard I/O port (0x130) if 1, otherwise the
-			value given is the I/O port to use (typically 0x1b0).
-			By default set to 1 if CONFIG_PATA_WINBOND_VLB_MODULE,
-			0 otherwise.
-
 	pata_platform.pio_mask=	[HW,LIBATA]
 			Format: <int>
 			Supported PIO mode mask.  Set individual bits to allow
-- 
2.53.0

Re: [PATCH v2 9/9] docs: kernel-parameters: Drop the pata_legacy.qdi and pata_legacy.winbond entries

[Karl Mehltretter]

On Sat, Sep 05, 2026 at 11:46:49AM +0100, Karl Mehltretter wrote:
> pata_legacy no longer has the qdi and winbond module parameters:
> commit 3c4d783f6922 ("ata: pata_legacy: remove VLB support") removed
> both together with the VLB controller support. The entries also refer
> to CONFIG_PATA_QDI_MODULE and CONFIG_PATA_WINBOND_VLB_MODULE, which do
> not exist either.
> 
> Drop both entries.
> 
> Fixes: 3c4d783f6922 ("ata: pata_legacy: remove VLB support")
> Assisted-by: LLM
> Signed-off-by: Karl Mehltretter <kmehltretter@gmail.com>
> Acked-by: Damien Le Moal <dlemoal@kernel.org>

This one is actually a duplicate, I just found out. Ethan posted a more
complete patch in June that removes all six pata_legacy entries which
commit 3c4d783f6922 ("ata: pata_legacy: remove VLB support") left
behind, this patch covers only two of them:

  https://lore.kernel.org/r/20260607064053.195166-1-enelsonmoore@gmail.com/

It has a Reviewed-by tag from Randy, but does not seem to
have been picked up yet. 

So I suggest: drop 9/9 and take Ethan's patch instead.
The other patches of this series are not affected.

Thanks,
Karl

Re: [PATCH v2 0/9] docs: kernel-parameters: Remove ten entries for parameters that no longer exist

[Arnd Bergmann]

On Sat, Sep 5, 2026, at 11:46, Karl Mehltretter wrote:
> kernel-parameters.txt still documents ten boot parameters whose parsing
> code was removed with the drivers or platforms that used them, one of
> them (atarimouse=) since before the git history. One patch per
> parameter, each with a Fixes: tag for the commit that removed the
> parser, so the maintainers of that area are on their own patch only;
> the two pata_legacy module parameters share the last one. Each entry
> was checked with git grep for its __setup(), early_param() and
> module_param() handler and with git log -S for the removing commit.

These all look good to me,

Acked-by: Arnd Bergmann <arnd@arndb.de>

If you have a script that you can easily run on another tree,
could you send me the script or the output for this one?

https://git.kernel.org/pub/scm/linux/kernel/git/soc/soc.git/log/?h=board-remove

I'm removing a bunch of code there, and if that ends up removing
additional documented paramenters, I'd like to fold the Documentation
update into the respective patches as well.

      Arnd

Re: [PATCH v2 0/9] docs: kernel-parameters: Remove ten entries for parameters that no longer exist

[Karl Mehltretter]

On Sat, Sep 05, 2026 at 12:12:51PM +0100, Arnd Bergmann wrote:
> On Sat, Sep 5, 2026, at 11:46, Karl Mehltretter wrote:
> > kernel-parameters.txt still documents ten boot parameters whose parsing
> > code was removed with the drivers or platforms that used them, one of
> > them (atarimouse=) since before the git history. One patch per
> > parameter, each with a Fixes: tag for the commit that removed the
> > parser, so the maintainers of that area are on their own patch only;
> > the two pata_legacy module parameters share the last one. Each entry
> > was checked with git grep for its __setup(), early_param() and
> > module_param() handler and with git log -S for the removing commit.
> 
> These all look good to me,
> 
> Acked-by: Arnd Bergmann <arnd@arndb.de>
> 
> If you have a script that you can easily run on another tree,
> could you send me the script or the output for this one?
> 
> https://git.kernel.org/pub/scm/linux/kernel/git/soc/soc.git/log/?h=board-remove
> 

Thanks for the review! Yes, here is the script, improved a bit since the
series was made.

It does not show anything on your branch though. board-remove at
c12d647b0229 removes 40 registrations, none of them a documented
parameter that loses its parser. The three documented names among them
(debug, irq, noalign) are still registered by other code.

Run it with
    check-kernel-parameters.py -C ~/soc --diff 8d3ae59288f1 board-remove

Its report mode turned up a second batch of stale entries on mainline
(r128=, mga=, i810=, tdfx=, smart2=, shapers=, hd=, goldfish, js= and a
few more), which I might send later.

Thanks
Karl

The script:

#!/usr/bin/env python3
# SPDX-License-Identifier: GPL-2.0
"""Find documented boot parameters that nothing parses any more.

Reads Documentation/admin-guide/kernel-parameters.txt at a git revision and
looks for the registration of every documented name in the code at the same
revision: __setup(), early_param(), core_param(), module_param() and friends.
Names without a registration are printed together with whether the name at
least still appears as a string somewhere (cmdline_find_option() style
parsing), so a human can decide. A parameter that was only ever parsed by
hand, without any of the macros, is invisible in both modes.

Usage:
    check-kernel-parameters.py [-C tree] [REV]           report for one revision
    check-kernel-parameters.py [-C tree] --diff A B      names parsed at A but not at B

Runs entirely on git objects (git grep / git show), no checkout needed.
"""
import argparse, re, subprocess, sys

REG = r'(__setup|__setup_param|early_param|early_param_on_off|core_param|core_param_unsafe|late_param|module_param|module_param_unsafe|module_param_named|module_param_named_unsafe|module_param_cb|module_param_cb_unsafe|module_param_call|device_param_cb|module_param_string|module_param_array|module_param_array_named|module_param_hw|module_param_hw_named|module_param_hw_array|__core_param_cb|torture_param|param_check_\w+)\s*\('
LEGEND_STOP = 'Kernel parameters'   # the tag legend ends at this heading, the parameter list follows

def git(tree, *a):
    r = subprocess.run(['git', '-C', tree, *a], capture_output=True, text=True, errors='replace')
    if r.returncode and 'grep' not in a[0]:
        sys.exit(f'git {a[0]} failed: {r.stderr.strip()}')
    return r.stdout

def documented(tree, rev):
    """Return {name: line} for every parameter entry in kernel-parameters.txt at rev."""
    txt = git(tree, 'show', f'{rev}:Documentation/admin-guide/kernel-parameters.txt')
    names = {}
    in_list = False
    for n, line in enumerate(txt.split('\n'), 1):
        if not in_list:
            if line.strip() == LEGEND_STOP: in_list = True
            continue
        m = re.match(r'^\t([A-Za-z][A-Za-z0-9_.-]*)(?:=|\s|$)', line)
        if not m: continue
        name = m.group(1)
        if name.isupper() and '.' not in name: continue     # a stray tag, not a parameter
        names.setdefault(name, n)
    return names

def registered(tree, rev):
    """Return the set of names registered by the parameter macros at rev."""
    out = git(tree, 'grep', '-h', '-E', REG, rev, '--', ':!Documentation', ':!tools', ':!scripts')
    names = set()
    for line in out.split('\n'):
        for m in re.finditer(REG + r'\s*"?([A-Za-z0-9_.-]+)', line):
            name = m.group(2)
            if m.group(1) == 'torture_param':     # torture_param(type, name, init, msg): the type comes first
                mm = re.search(r'torture_param\s*\(\s*\w+\s*,\s*([A-Za-z0-9_]+)', line)
                if mm: name = mm.group(1)
            names.add(name.rstrip('='))
    return names

def string_hits(tree, rev, name):
    """Files at rev that contain the name as a quoted string (manual command line parsing);
    a dotted name is looked up whole first (arm64.nobti style tables), then by its last part."""
    for probe in ([name, name.rsplit('.', 1)[-1]] if '.' in name else [name]):
        out = git(tree, 'grep', '-l', '-F', f'"{probe}', rev, '--', ':!Documentation', ':!tools', ':!scripts')
        hits = [l.split(':', 1)[1] for l in out.split('\n') if l]
        if hits: return hits
    return []

def parsed_at(tree, rev):
    docs = documented(tree, rev)
    regs = registered(tree, rev)
    def ok(name):
        if name in regs: return True
        base = name.rsplit('.', 1)[-1]          # module.param= is registered as module_param(param)
        return base in regs
    return docs, {n for n in docs if ok(n)}

def report(tree, rev):
    docs, ok = parsed_at(tree, rev)
    missing = sorted(n for n in docs if n not in ok)
    print(f'{len(docs)} documented parameters at {rev}, {len(missing)} without a registration macro:')
    for n in missing:
        hits = string_hits(tree, rev, n)
        tag = f'string appears in {hits[0]}' + (f' (+{len(hits)-1})' if len(hits) > 1 else '') if hits else 'NOT FOUND anywhere'
        print(f'  {n:40} kernel-parameters.txt:{docs[n]:<6} {tag}')

def diff(tree, a, b):
    docs_a, ok_a = parsed_at(tree, a)
    docs_b, ok_b = parsed_at(tree, b)
    lost = sorted(n for n in ok_a if n in docs_b and n not in ok_b)
    print(f'documented parameters parsed at {a} but no longer at {b}: {len(lost)}')
    for n in lost:
        hits = string_hits(tree, b, n)
        print(f'  {n:40} kernel-parameters.txt:{docs_b[n]:<6} ' + (f'string still in {hits[0]}' if hits else 'no string left either'))

if __name__ == '__main__':
    ap = argparse.ArgumentParser()
    ap.add_argument('-C', dest='tree', default='.')
    ap.add_argument('--diff', nargs=2, metavar=('A', 'B'))
    ap.add_argument('rev', nargs='?', default='HEAD')
    a = ap.parse_args()
    if a.diff: diff(a.tree, *a.diff)
    else: report(a.tree, a.rev)