linux.git/arch/riscv/kernel/module.c, branch v6.9

riscv: optimize ELF relocation function in riscv

2024-01-18T02:21:10+00:00

The patch can optimize the running times of insmod command by modify ELF
relocation function.
In the 5.10 and latest kernel, when install the riscv ELF drivers which
contains multiple symbol table items to be relocated, kernel takes a lot
of time to execute the relocation. For example, we install a 3+MB driver
need 180+s.
We focus on the riscv architecture handle R_RISCV_HI20 and R_RISCV_LO20
type items relocation function in the arch\riscv\kernel\module.c and
find that there are two-loops in the function. If we modify the begin
number in the second for-loops iteration, we could save significant time
for installation. We install the same 3+MB driver could just need 2s.

Signed-off-by: Amma Lee 
Signed-off-by: Maxim Kochetkov 
Reviewed-by: Charlie Jenkins 
Link: https://lore.kernel.org/r/20231214063906.13612-1-fido_max@inbox.ru
Signed-off-by: Palmer Dabbelt

Merge patch series "riscv: modules: Fix module loading error handling"

2024-01-11T15:36:25+00:00

Charlie Jenkins  says:

When modules are loaded while there is not ample allocatable memory,
there was previously not proper error handling. This series fixes a
use-after-free error and a different issue that caused a non graceful
exit after memory was not properly allocated.

* b4-shazam-merge:
  riscv: Fix relocation_hashtable size
  riscv: Correctly free relocation hashtable on error
  riscv: Fix module loading free order

Link: https://lore.kernel.org/r/20240104-module_loading_fix-v3-0-a71f8de6ce0f@rivosinc.com
Signed-off-by: Palmer Dabbelt

riscv: Fix relocation_hashtable size

2024-01-10T14:48:13+00:00

A second dereference is needed to get the accurate size of the
relocation_hashtable.

Signed-off-by: Charlie Jenkins 
Fixes: d8792a5734b0 ("riscv: Safely remove entries from relocation list")
Reported-by: kernel test robot 
Reported-by: Julia Lawall 
Closes: https://lore.kernel.org/r/202312120044.wTI1Uyaa-lkp@intel.com/
Reviewed-by: Dan Carpenter 
Link: https://lore.kernel.org/r/20240104-module_loading_fix-v3-3-a71f8de6ce0f@rivosinc.com
Signed-off-by: Palmer Dabbelt

riscv: Correctly free relocation hashtable on error

2024-01-10T14:48:12+00:00

When there is not enough allocatable memory for the relocation
hashtable, module loading should exit gracefully. Previously, this was
attempted to be accomplished by checking if an unsigned number is less
than zero which does not work. Instead have the caller check if the
hashtable was correctly allocated and add a comment explaining that
hashtable_bits that is 0 is valid.

Signed-off-by: Charlie Jenkins 
Fixes: d8792a5734b0 ("riscv: Safely remove entries from relocation list")
Reported-by: kernel test robot 
Reported-by: Dan Carpenter 
Closes: https://lore.kernel.org/r/202312132019.iYGTwW0L-lkp@intel.com/
Reported-by: kernel test robot 
Reported-by: Julia Lawall 
Closes: https://lore.kernel.org/r/202312120044.wTI1Uyaa-lkp@intel.com/
Reviewed-by: Dan Carpenter 
Link: https://lore.kernel.org/r/20240104-module_loading_fix-v3-2-a71f8de6ce0f@rivosinc.com
Signed-off-by: Palmer Dabbelt

riscv: Fix module loading free order

2024-01-10T14:48:11+00:00

Reverse order of kfree calls to resolve use-after-free error.

Signed-off-by: Charlie Jenkins 
Fixes: d8792a5734b0 ("riscv: Safely remove entries from relocation list")
Reported-by: kernel test robot 
Reported-by: Dan Carpenter 
Closes: https://lore.kernel.org/r/202312132019.iYGTwW0L-lkp@intel.com/
Reported-by: kernel test robot 
Reported-by: Julia Lawall 
Closes: https://lore.kernel.org/r/202312120044.wTI1Uyaa-lkp@intel.com/
Reviewed-by: Dan Carpenter 
Link: https://lore.kernel.org/r/20240104-module_loading_fix-v3-1-a71f8de6ce0f@rivosinc.com
Signed-off-by: Palmer Dabbelt

riscv: Fix module_alloc() that did not reset the linear mapping permissions

2024-01-09T18:59:07+00:00

After unloading a module, we must reset the linear mapping permissions,
see the example below:

Before unloading a module:

0xffffaf809d65d000-0xffffaf809d6dc000    0x000000011d65d000       508K PTE .   ..     ..   D A G . . W R V
0xffffaf809d6dc000-0xffffaf809d6dd000    0x000000011d6dc000         4K PTE .   ..     ..   D A G . . . R V
0xffffaf809d6dd000-0xffffaf809d6e1000    0x000000011d6dd000        16K PTE .   ..     ..   D A G . . W R V
0xffffaf809d6e1000-0xffffaf809d6e7000    0x000000011d6e1000        24K PTE .   ..     ..   D A G . X . R V

After unloading a module:

0xffffaf809d65d000-0xffffaf809d6e1000    0x000000011d65d000       528K PTE .   ..     ..   D A G . . W R V
0xffffaf809d6e1000-0xffffaf809d6e7000    0x000000011d6e1000        24K PTE .   ..     ..   D A G . X W R V

The last mapping is not reset and we end up with WX mappings in the linear
mapping.

So add VM_FLUSH_RESET_PERMS to our module_alloc() definition.

Fixes: 0cff8bff7af8 ("riscv: avoid the PIC offset of static percpu data in module beyond 2G limits")
Signed-off-by: Alexandre Ghiti 
Link: https://lore.kernel.org/r/20231213134027.155327-2-alexghiti@rivosinc.com
Signed-off-by: Palmer Dabbelt

riscv: Correct type casting in module loading

2023-12-04T19:02:38+00:00

Use __le16 with le16_to_cpu.

Fixes: 8fd6c5142395 ("riscv: Add remaining module relocations")
Signed-off-by: Charlie Jenkins 
Reviewed-by: Samuel Holland 
Tested-by: Samuel Holland 
Tested-by: Björn Töpel 
Link: https://lore.kernel.org/r/20231127-module_linking_freeing-v4-2-a2ca1d7027d0@rivosinc.com
Signed-off-by: Palmer Dabbelt

riscv: Safely remove entries from relocation list

2023-12-04T19:02:37+00:00

Use the safe versions of list and hlist iteration to safely remove
entries from the module relocation lists. To allow mutliple threads to
load modules concurrently, move relocation list pointers onto the stack
rather than using global variables.

Fixes: 8fd6c5142395 ("riscv: Add remaining module relocations")
Reported-by: Ron Economos 
Closes: https://lore.kernel.org/linux-riscv/444de86a-7e7c-4de7-5d1d-c1c40eefa4ba@w6rz.net
Signed-off-by: Charlie Jenkins 
Tested-by: Björn Töpel 
Link: https://lore.kernel.org/r/20231127-module_linking_freeing-v4-1-a2ca1d7027d0@rivosinc.com
Signed-off-by: Palmer Dabbelt

RISC-V: Don't rely on positional structure initialization

2023-11-07T23:00:05+00:00

Without this I get a bunch of warnings along the lines of

    arch/riscv/kernel/module.c:535:26: error: positional initialization of field in 'struct' declared with 'designated_init' attribute [-Werror=designated-init]
      535 |         [R_RISCV_32] = { apply_r_riscv_32_rela },

This just mades the member initializers explicit instead of positional.
I also aligned some of the table, but mostly just to make the batch
editing go faster.

Fixes: b51fc88cb35e ("Merge patch series "riscv: Add remaining module relocations and tests"")
Reviewed-by: Charlie Jenkins 
Link: https://lore.kernel.org/r/20231107155529.8368-1-palmer@rivosinc.com
Signed-off-by: Palmer Dabbelt

riscv: Add remaining module relocations

2023-11-07T22:59:31+00:00

Add all final module relocations and add error logs explaining the ones
that are not supported. Implement overflow checks for
ADD/SUB/SET/ULEB128 relocations.

Signed-off-by: Charlie Jenkins 
Link: https://lore.kernel.org/r/20231101-module_relocations-v9-2-8dfa3483c400@rivosinc.com
Signed-off-by: Palmer Dabbelt