arm64: kernel: Remove early fdt remap code

The early FDT remap code is no longer used so let's drop it.

Signed-off-by: Ard Biesheuvel <[email protected]>
Link: https://lore.kernel.org/r/2024021412284

arm64: kernel: Remove early fdt remap code

The early FDT remap code is no longer used so let's drop it.

Signed-off-by: Ard Biesheuvel <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Catalin Marinas <[email protected]>

show more ...

arm64: mm: Fix "rodata=on" when CONFIG_RODATA_FULL_DEFAULT_ENABLED=y

When CONFIG_RODATA_FULL_DEFAULT_ENABLED=y, passing "rodata=on" on the
kernel command-line (rather than "rodata=full") should turn

arm64: mm: Fix "rodata=on" when CONFIG_RODATA_FULL_DEFAULT_ENABLED=y

When CONFIG_RODATA_FULL_DEFAULT_ENABLED=y, passing "rodata=on" on the
kernel command-line (rather than "rodata=full") should turn off the
"full" behaviour, leaving writable linear aliases of read-only kernel
memory. Unfortunately, the option has no effect in this situation and
the only way to disable the "rodata=full" behaviour is to disable rodata
protection entirely by passing "rodata=off".

Fix this by parsing the "on" and "off" options in the arch code,
additionally enforcing that 'rodata_full' cannot be set without also
setting 'rodata_enabled', allowing us to simplify a couple of checks
in the process.

Fixes: 2e8cff0a0eee ("arm64: fix rodata=full")
Cc: Ard Biesheuvel <[email protected]>
Cc: Mark Rutland <[email protected]>
Signed-off-by: Will Deacon <[email protected]>
Reviewed-by: "Russell King (Oracle)" <[email protected]>
Reviewed-by: Ard Biesheuvel <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Catalin Marinas <[email protected]>

show more ...

arm64: fix rodata=full

On arm64, "rodata=full" has been suppored (but not documented) since
commit:

c55191e96caa9d78 ("arm64: mm: apply r/o permissions of VM areas to its linear alias as well")

arm64: fix rodata=full

On arm64, "rodata=full" has been suppored (but not documented) since
commit:

c55191e96caa9d78 ("arm64: mm: apply r/o permissions of VM areas to its linear alias as well")

As it's necessary to determine the rodata configuration early during
boot, arm64 has an early_param() handler for this, whereas init/main.c
has a __setup() handler which is run later.

Unfortunately, this split meant that since commit:

f9a40b0890658330 ("init/main.c: return 1 from handled __setup() functions")

... passing "rodata=full" would result in a spurious warning from the
__setup() handler (though RO permissions would be configured
appropriately).

Further, "rodata=full" has been broken since commit:

0d6ea3ac94ca77c5 ("lib/kstrtox.c: add "false"/"true" support to kstrtobool()")

... which caused strtobool() to parse "full" as false (in addition to
many other values not documented for the "rodata=" kernel parameter.

This patch fixes this breakage by:

* Moving the core parameter parser to an __early_param(), such that it
is available early.

* Adding an (optional) arch hook which arm64 can use to parse "full".

* Updating the documentation to mention that "full" is valid for arm64.

* Having the core parameter parser handle "on" and "off" explicitly,
such that any undocumented values (e.g. typos such as "ful") are
reported as errors rather than being silently accepted.

Note that __setup() and early_param() have opposite conventions for
their return values, where __setup() uses 1 to indicate a parameter was
handled and early_param() uses 0 to indicate a parameter was handled.

Fixes: f9a40b089065 ("init/main.c: return 1 from handled __setup() functions")
Fixes: 0d6ea3ac94ca ("lib/kstrtox.c: add "false"/"true" support to kstrtobool()")
Signed-off-by: Mark Rutland <[email protected]>
Cc: Andy Shevchenko <[email protected]>
Cc: Ard Biesheuvel <[email protected]>
Cc: Catalin Marinas <[email protected]>
Cc: Jagdish Gediya <[email protected]>
Cc: Matthew Wilcox <[email protected]>
Cc: Randy Dunlap <[email protected]>
Cc: Will Deacon <[email protected]>
Reviewed-by: Ard Biesheuvel <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Will Deacon <[email protected]>

show more ...

arm64: fix KASAN_INLINE

Since commit:

a004393f45d9a55e ("arm64: idreg-override: use early FDT mapping in ID map")

Kernels built with KASAN_INLINE=y die early in boot before producing any
console

arm64: fix KASAN_INLINE

Since commit:

a004393f45d9a55e ("arm64: idreg-override: use early FDT mapping in ID map")

Kernels built with KASAN_INLINE=y die early in boot before producing any
console output. This is because the accesses made to the FDT (e.g. in
generic string processing functions) are instrumented with KASAN, and
with KASAN_INLINE=y any access to an address in TTBR0 results in a bogus
shadow VA, resulting in a data abort.

This patch fixes this by reverting commits:

7559d9f97581654f ("arm64: setup: drop early FDT pointer helpers")
bd0c3fa21878b6d0 ("arm64: idreg-override: use early FDT mapping in ID map")

... and using the TTBR1 fixmap mapping of the FDT.

Note that due to a later commit:

b65e411d6cc2f12a ("arm64: Save state of HCR_EL2.E2H before switch to EL1")

... which altered the prototype of init_feature_override() (and
invocation from head.S), commit bd0c3fa21878b6d0 does not revert
cleanly, and I've fixed that up manually.

Fixes: a004393f45d9 ("arm64: idreg-override: use early FDT mapping in ID map")
Cc: Ard Biesheuvel <[email protected]>
Cc: Catalin Marinas <[email protected]>
Cc: Marc Zyngier <[email protected]>
Cc: Will Deacon <[email protected]>
Acked-by: Catalin Marinas <[email protected]>
Signed-off-by: Mark Rutland <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Will Deacon <[email protected]>

show more ...

arm64: setup: drop early FDT pointer helpers

We no longer need to call into the kernel to map the FDT before calling
into the kernel so let's drop the helpers we added for this.

Signed-off-by: Ard

arm64: setup: drop early FDT pointer helpers

We no longer need to call into the kernel to map the FDT before calling
into the kernel so let's drop the helpers we added for this.

Signed-off-by: Ard Biesheuvel <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Will Deacon <[email protected]>

show more ...

arm64: asm: setup.h: export common variables

When building the kernel with sparse enabled 'C=1' the following
warnings can be seen:

arch/arm64/kernel/setup.c:58:13: warning: symbol '__fdt_pointer'

arm64: asm: setup.h: export common variables

When building the kernel with sparse enabled 'C=1' the following
warnings can be seen:

arch/arm64/kernel/setup.c:58:13: warning: symbol '__fdt_pointer' was not declared. Should it be static?
arch/arm64/kernel/setup.c:84:25: warning: symbol 'boot_args' was not declared. Should it be static?

Rework so the variables are exported, since these two variable are
created and used in setup.c, also used in head.S.

Signed-off-by: Anders Roxell <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Will Deacon <[email protected]>

show more ...

arm64: Extract early FDT mapping from kaslr_early_init()

As we want to parse more options very early in the kernel lifetime,
let's always map the FDT early. This is achieved by moving that
code out

arm64: Extract early FDT mapping from kaslr_early_init()

As we want to parse more options very early in the kernel lifetime,
let's always map the FDT early. This is achieved by moving that
code out of kaslr_early_init().

No functional change expected.

Signed-off-by: Marc Zyngier <[email protected]>
Acked-by: Catalin Marinas <[email protected]>
Acked-by: David Brazdil <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
[will: Ensue KASAN is enabled before running C code]
Signed-off-by: Will Deacon <[email protected]>

show more ...

arm64: Kernel booting and initialisation

The patch adds the kernel booting and the initial setup code.
Documentation/arm64/booting.txt describes the booting protocol on the
AArch64 Linux kernel. Thi

arm64: Kernel booting and initialisation

The patch adds the kernel booting and the initial setup code.
Documentation/arm64/booting.txt describes the booting protocol on the
AArch64 Linux kernel. This is subject to change following the work on
boot standardisation, ACPI.

Signed-off-by: Will Deacon <[email protected]>
Signed-off-by: Catalin Marinas <[email protected]>
Acked-by: Nicolas Pitre <[email protected]>
Acked-by: Tony Lindgren <[email protected]>
Acked-by: Olof Johansson <[email protected]>
Acked-by: Santosh Shilimkar <[email protected]>
Acked-by: Arnd Bergmann <[email protected]>

show more ...