linux.git/arch/parisc/include/asm/assembly.h, branch for-next

parisc: Avoid clobbering the C/B bits in the PSW with tophys and tovirt macros

2024-02-27T21:51:44+00:00

Use add,l to avoid clobbering the C/B bits in the PSW.

Signed-off-by: John David Anglin 
Signed-off-by: Helge Deller 
Cc: stable@vger.kernel.org # v5.10+

parisc: Fix random data corruption from exception handler

2024-01-30T16:18:58+00:00

The current exception handler implementation, which assists when accessing
user space memory, may exhibit random data corruption if the compiler decides
to use a different register than the specified register %r29 (defined in
ASM_EXCEPTIONTABLE_REG) for the error code. If the compiler choose another
register, the fault handler will nevertheless store -EFAULT into %r29 and thus
trash whatever this register is used for.
Looking at the assembly I found that this happens sometimes in emulate_ldd().

To solve the issue, the easiest solution would be if it somehow is
possible to tell the fault handler which register is used to hold the error
code. Using %0 or %1 in the inline assembly is not posssible as it will show
up as e.g. %r29 (with the "%r" prefix), which the GNU assembler can not
convert to an integer.

This patch takes another, better and more flexible approach:
We extend the __ex_table (which is out of the execution path) by one 32-word.
In this word we tell the compiler to insert the assembler instruction
"or %r0,%r0,%reg", where %reg references the register which the compiler
choosed for the error return code.
In case of an access failure, the fault handler finds the __ex_table entry and
can examine the opcode. The used register is encoded in the lowest 5 bits, and
the fault handler can then store -EFAULT into this register.

Since we extend the __ex_table to 3 words we can't use the BUILDTIME_TABLE_SORT
config option any longer.

Signed-off-by: Helge Deller 
Cc:  # v6.0+

parisc: Mark ex_table entries 32-bit aligned in assembly.h

2023-11-25T08:43:17+00:00

Add an align statement to tell the linker that all ex_table entries and as
such the whole ex_table section should be 32-bit aligned in vmlinux and modules.

Signed-off-by: Helge Deller 
Cc: stable@vger.kernel.org   # v6.0+

parisc: Delete redundant register definitions in

2023-06-17T04:48:11+00:00

We define sp and ipsw in  using ".reg", and when using
current binutils (snapshot 2.40.50.20230611) the definitions in
 using "=" conflict with those:

arch/parisc/include/asm/assembly.h: Assembler messages:
arch/parisc/include/asm/assembly.h:93: Error: symbol `sp' is already defined
arch/parisc/include/asm/assembly.h:95: Error: symbol `ipsw' is already defined

Delete the duplicate definitions in .

Also delete the definition of gp, which isn't used anywhere.

Signed-off-by: Ben Hutchings 
Cc: stable@vger.kernel.org # v6.0+
Signed-off-by: Helge Deller

parisc: Add dep_safe() macro to deposit a register in 32- and 64-kernels

2022-05-23T11:44:24+00:00

Signed-off-by: Helge Deller

parisc: Fix wrong comment for shr macro

2022-05-23T11:44:24+00:00

The comment that the source and target register can not be the same is
wrong. Instead on PA2.0 usage of extru can clobber upper 32-bits.
This patch fixes the comment.

Signed-off-by: Helge Deller

parisc: Add defines for various space register

2022-03-11T18:49:30+00:00

Provide defines for space registers (SR_KERNEL, SR_USER, ...) which
should be used instead of hardcoding the values.

Signed-off-by: Helge Deller

parisc: Define depi_safe macro

2022-01-07T00:29:20+00:00

The depi instruction is similar to the extru instruction on 64-bit machines.
It leaves the most-significant 32 bits of the target register in an undefined
state.  On 64-bit machines, the macro uses depdi to perform safe deposits in
the least-significant 32 bits.

Signed-off-by: John David Anglin 
Signed-off-by: Helge Deller

parisc: Provide an extru_safe() macro to extract unsigned bits

2021-11-22T06:37:31+00:00

The extru instruction leaves the most significant 32 bits of the
target register in an undefined state on PA 2.0 systems.
Provide a macro to safely use extru on 32- and 64-bit machines.

Suggested-by: John David Anglin 
Signed-off-by: Helge Deller

parisc: Wrap assembler related defines inside ASSEMBLY

2021-11-18T08:02:00+00:00

Building allmodconfig shows errors in the gpu/drm/msm snapdragon drivers,
because a COND() define is used there which conflicts with the COND() for
PA-RISC assembly.  Although the snapdragon driver isn't relevant for parisc, it
is nevertheless compiled when CONFIG_COMPILE_TEST is defined.

Move the COND() define and other PA-RISC mnemonics inside the #ifdef
__ASSEMBLY__ part to avoid this conflict.

Signed-off-by: Helge Deller 
Reported-by: kernel test robot