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riscv: Fix text patching when IPI are used

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BugLink: https://bugs.launchpad.net/bugs/2106770

[ Upstream commit c97bf629963e52b205ed5fbaf151e5bd342f9c63 ]

For now, we use stop_machine() to patch the text and when we use IPIs for
remote icache flushes (which is emitted in patch_text_nosync()), the system
hangs.

So instead, make sure every CPU executes the stop_machine() patching
function and emit a local icache flush there.

Co-developed-by: Björn Töpel <bjorn@rivosinc.com>
Signed-off-by: Björn Töpel <bjorn@rivosinc.com>
Signed-off-by: Alexandre Ghiti <alexghiti@rivosinc.com>
Reviewed-by: Andrea Parri <parri.andrea@gmail.com>
Link: https://lore.kernel.org/r/20240229121056.203419-3-alexghiti@rivosinc.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
Stable-dep-of: 13134cc94914 ("riscv: kprobes: Fix incorrect address calculation")
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Manuel Diewald <manuel.diewald@canonical.com>
Signed-off-by: Mehmet Basaran <mehmet.basaran@canonical.com>
This commit is contained in:
Alexandre Ghiti
2024-02-29 13:10:56 +01:00
committed by Mehmet Basaran
parent 8f51c0715e
commit d2d85f20ee
3 changed files with 53 additions and 8 deletions
Download Patch File Download Diff File Expand all files Collapse all files
arch/riscv/kernel/patch.c
+12 -4
View File
@@ -196,7 +196,7 @@ int patch_text_set_nosync(void *addr, u8 c, size_t len)
}
NOKPROBE_SYMBOL(patch_text_set_nosync);
static int patch_insn_write(void *addr, const void *insn, size_t len)
int patch_insn_write(void *addr, const void *insn, size_t len)
{
size_t patched = 0;
size_t size;
@@ -240,16 +240,24 @@ static int patch_text_cb(void *data)
if (atomic_inc_return(&patch->cpu_count) == num_online_cpus()) {
for (i = 0; ret == 0 && i < patch->ninsns; i++) {
len = GET_INSN_LENGTH(patch->insns[i]);
ret = patch_text_nosync(patch->addr + i * len,
&patch->insns[i], len);
ret = patch_insn_write(patch->addr + i * len, &patch->insns[i], len);
}
atomic_inc(&patch->cpu_count);
/*
* Make sure the patching store is effective *before* we
* increment the counter which releases all waiting CPUs
* by using the release variant of atomic increment. The
* release pairs with the call to local_flush_icache_all()
* on the waiting CPU.
*/
atomic_inc_return_release(&patch->cpu_count);
} else {
while (atomic_read(&patch->cpu_count) <= num_online_cpus())
cpu_relax();
smp_mb();
}
local_flush_icache_all();
return ret;
}
NOKPROBE_SYMBOL(patch_text_cb);