From: Puranjay Mohan <puranjay12@gmail.com>
To: paul.walmsley@sifive.com, palmer@dabbelt.com,
aou@eecs.berkeley.edu, pulehui@huawei.com,
conor.dooley@microchip.com, ast@kernel.org, daniel@iogearbox.net,
andrii@kernel.org, martin.lau@linux.dev, song@kernel.org,
yhs@fb.com, kpsingh@kernel.org, bjorn@kernel.org,
bpf@vger.kernel.org, linux-riscv@lists.infradead.org,
linux-kernel@vger.kernel.org
Cc: puranjay12@gmail.com
Subject: [PATCH bpf-next 1/2] riscv: Extend patch_text_nosync() for multiple pages
Date: Thu, 20 Jul 2023 15:49:40 +0000 [thread overview]
Message-ID: <20230720154941.1504-2-puranjay12@gmail.com> (raw)
In-Reply-To: <20230720154941.1504-1-puranjay12@gmail.com>
The patch_insn_write() function currently doesn't work for multiple
pages of instructions, therefore patch_text_nosync() will fail with a
page fault if called with lengths spanning multiple pages.
This commit extends the patch_insn_write() function to support multiple
pages by copying at max 2 pages at a time in a loop. This implementation
is similar to text_poke_copy() function of x86.
Signed-off-by: Puranjay Mohan <puranjay12@gmail.com>
---
arch/riscv/kernel/patch.c | 29 ++++++++++++++++++++++++-----
1 file changed, 24 insertions(+), 5 deletions(-)
diff --git a/arch/riscv/kernel/patch.c b/arch/riscv/kernel/patch.c
index 575e71d6c8ae..b2dbfcfdef85 100644
--- a/arch/riscv/kernel/patch.c
+++ b/arch/riscv/kernel/patch.c
@@ -53,7 +53,7 @@ static void patch_unmap(int fixmap)
}
NOKPROBE_SYMBOL(patch_unmap);
-static int patch_insn_write(void *addr, const void *insn, size_t len)
+static int __patch_insn_write(void *addr, const void *insn, size_t len)
{
void *waddr = addr;
bool across_pages = (((uintptr_t) addr & ~PAGE_MASK) + len) > PAGE_SIZE;
@@ -74,7 +74,7 @@ static int patch_insn_write(void *addr, const void *insn, size_t len)
lockdep_assert_held(&text_mutex);
if (across_pages)
- patch_map(addr + len, FIX_TEXT_POKE1);
+ patch_map(addr + PAGE_SIZE, FIX_TEXT_POKE1);
waddr = patch_map(addr, FIX_TEXT_POKE0);
@@ -87,15 +87,34 @@ static int patch_insn_write(void *addr, const void *insn, size_t len)
return ret;
}
-NOKPROBE_SYMBOL(patch_insn_write);
+NOKPROBE_SYMBOL(__patch_insn_write);
#else
-static int patch_insn_write(void *addr, const void *insn, size_t len)
+static int __patch_insn_write(void *addr, const void *insn, size_t len)
{
return copy_to_kernel_nofault(addr, insn, len);
}
-NOKPROBE_SYMBOL(patch_insn_write);
+NOKPROBE_SYMBOL(__patch_insn_write);
#endif /* CONFIG_MMU */
+static int patch_insn_write(void *addr, const void *insn, size_t len)
+{
+ size_t patched = 0;
+ size_t size;
+ int ret = 0;
+
+ while (patched < len && !ret) {
+ size = min_t(size_t,
+ PAGE_SIZE * 2 - offset_in_page(addr + patched),
+ len - patched);
+ ret = __patch_insn_write(addr + patched, insn + patched, size);
+
+ patched += size;
+ }
+
+ return ret;
+}
+NOKPROBE_SYMBOL(patch_insn_write);
+
int patch_text_nosync(void *addr, const void *insns, size_t len)
{
u32 *tp = addr;
--
2.40.1
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next prev parent reply other threads:[~2023-07-20 15:49 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-07-20 15:49 [PATCH bpf-next 0/2] bpf, riscv: use BPF prog pack allocator in BPF JIT Puranjay Mohan
2023-07-20 15:49 ` Puranjay Mohan [this message]
2023-08-13 20:20 ` [PATCH bpf-next 1/2] riscv: Extend patch_text_nosync() for multiple pages Björn Töpel
2023-07-20 15:49 ` [PATCH bpf-next 2/2] bpf, riscv: use prog pack allocator in the BPF JIT Puranjay Mohan
2023-07-22 9:24 ` [PATCH bpf-next 0/2] bpf, riscv: use BPF prog pack allocator in " Björn Töpel
2023-08-13 20:27 ` Björn Töpel
2023-08-14 6:14 ` Björn Töpel
2023-08-14 9:12 ` Björn Töpel
2023-08-14 9:42 ` Puranjay Mohan
2023-08-14 10:06 ` Björn Töpel
2023-08-14 10:40 ` Björn Töpel
2023-08-14 12:05 ` Puranjay Mohan
2023-08-14 14:29 ` Björn Töpel
2023-08-14 15:38 ` Puranjay Mohan
2023-08-14 18:30 ` Björn Töpel
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