| Message ID | 20230828165958.1714079-3-puranjay12@gmail.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | bpf, riscv: use BPF prog pack allocator in BPF JIT | expand |
| Context | Check | Description |
|---|---|---|
| conchuod/tree_selection | fail | Failed to apply to next/pending-fixes, riscv/for-next or riscv/master |
On 2023/8/29 0:59, Puranjay Mohan wrote: > The BPF JIT needs to write invalid instructions to RX regions of memory to > invalidate removed BPF programs. This needs a function like memset() that > can work with RX memory. > > Implement patch_text_set_nosync() which is similar to text_poke_set() of > x86. > > Signed-off-by: Puranjay Mohan <puranjay12@gmail.com> > --- > arch/riscv/include/asm/patch.h | 1 + > arch/riscv/kernel/patch.c | 77 ++++++++++++++++++++++++++++++++++ > 2 files changed, 78 insertions(+) > > diff --git a/arch/riscv/include/asm/patch.h b/arch/riscv/include/asm/patch.h > index 63c98833d510..e88b52d39eac 100644 > --- a/arch/riscv/include/asm/patch.h > +++ b/arch/riscv/include/asm/patch.h > @@ -7,6 +7,7 @@ > #define _ASM_RISCV_PATCH_H > > int patch_text_nosync(void *addr, const void *insns, size_t len); > +int patch_text_set_nosync(void *addr, u8 c, size_t len); > int patch_text(void *addr, u32 *insns, int ninsns); > > extern int riscv_patch_in_stop_machine; > diff --git a/arch/riscv/kernel/patch.c b/arch/riscv/kernel/patch.c > index 2c97e246f4dc..13ee7bf589a1 100644 > --- a/arch/riscv/kernel/patch.c > +++ b/arch/riscv/kernel/patch.c > @@ -6,6 +6,7 @@ > #include <linux/spinlock.h> > #include <linux/mm.h> > #include <linux/memory.h> > +#include <linux/string.h> > #include <linux/uaccess.h> > #include <linux/stop_machine.h> > #include <asm/kprobes.h> > @@ -53,6 +54,39 @@ static void patch_unmap(int fixmap) > } > NOKPROBE_SYMBOL(patch_unmap); > > +static int __patch_insn_set(void *addr, u8 c, size_t len) > +{ > + void *waddr = addr; > + bool across_pages = (((uintptr_t)addr & ~PAGE_MASK) + len) > PAGE_SIZE; > + > + /* > + * Only two pages can be mapped at a time for writing. > + */ > + if (len + offset_in_page(addr) > 2 * PAGE_SIZE) > + return -EINVAL; > + /* > + * Before reaching here, it was expected to lock the text_mutex > + * already, so we don't need to give another lock here and could > + * ensure that it was safe between each cores. > + */ > + lockdep_assert_held(&text_mutex); > + > + if (across_pages) > + patch_map(addr + PAGE_SIZE, FIX_TEXT_POKE1); > + > + waddr = patch_map(addr, FIX_TEXT_POKE0); > + > + memset(waddr, c, len); > + > + patch_unmap(FIX_TEXT_POKE0); > + > + if (across_pages) > + patch_unmap(FIX_TEXT_POKE1); > + > + return 0; > +} > +NOKPROBE_SYMBOL(__patch_insn_set); > + > static int __patch_insn_write(void *addr, const void *insn, size_t len) > { > void *waddr = addr; > @@ -95,6 +129,14 @@ static int __patch_insn_write(void *addr, const void *insn, size_t len) > } > NOKPROBE_SYMBOL(__patch_insn_write); > #else > +static int __patch_insn_set(void *addr, u8 c, size_t len) > +{ > + memset(addr, c, len); > + > + return 0; > +} > +NOKPROBE_SYMBOL(__patch_insn_set); > + > static int __patch_insn_write(void *addr, const void *insn, size_t len) > { > return copy_to_kernel_nofault(addr, insn, len); > @@ -102,6 +144,41 @@ static int __patch_insn_write(void *addr, const void *insn, size_t len) > NOKPROBE_SYMBOL(__patch_insn_write); > #endif /* CONFIG_MMU */ > > +static int patch_insn_set(void *addr, u8 c, size_t len) > +{ > + size_t patched = 0; > + size_t size; > + int ret = 0; > + > + /* > + * __patch_insn_set() can only work on 2 pages at a time so call it in a > + * loop with len <= 2 * PAGE_SIZE. > + */ > + while (patched < len && !ret) { > + size = min_t(size_t, PAGE_SIZE * 2 - offset_in_page(addr + patched), len - patched); > + ret = __patch_insn_set(addr + patched, c, size); > + > + patched += size; > + } > + > + return ret; > +} > +NOKPROBE_SYMBOL(patch_insn_set); > + > +int patch_text_set_nosync(void *addr, u8 c, size_t len) > +{ > + u32 *tp = addr; > + int ret; > + > + ret = patch_insn_set(tp, c, len); > + > + if (!ret) > + flush_icache_range((uintptr_t)tp, (uintptr_t)tp + len); > + > + return ret; > +} > +NOKPROBE_SYMBOL(patch_text_set_nosync); > + > static int patch_insn_write(void *addr, const void *insn, size_t len) > { > size_t patched = 0; Reviewed-by: Pu Lehui <pulehui@huawei.com>
diff --git a/arch/riscv/include/asm/patch.h b/arch/riscv/include/asm/patch.h index 63c98833d510..e88b52d39eac 100644 --- a/arch/riscv/include/asm/patch.h +++ b/arch/riscv/include/asm/patch.h @@ -7,6 +7,7 @@ #define _ASM_RISCV_PATCH_H int patch_text_nosync(void *addr, const void *insns, size_t len); +int patch_text_set_nosync(void *addr, u8 c, size_t len); int patch_text(void *addr, u32 *insns, int ninsns); extern int riscv_patch_in_stop_machine; diff --git a/arch/riscv/kernel/patch.c b/arch/riscv/kernel/patch.c index 2c97e246f4dc..13ee7bf589a1 100644 --- a/arch/riscv/kernel/patch.c +++ b/arch/riscv/kernel/patch.c @@ -6,6 +6,7 @@ #include <linux/spinlock.h> #include <linux/mm.h> #include <linux/memory.h> +#include <linux/string.h> #include <linux/uaccess.h> #include <linux/stop_machine.h> #include <asm/kprobes.h> @@ -53,6 +54,39 @@ static void patch_unmap(int fixmap) } NOKPROBE_SYMBOL(patch_unmap); +static int __patch_insn_set(void *addr, u8 c, size_t len) +{ + void *waddr = addr; + bool across_pages = (((uintptr_t)addr & ~PAGE_MASK) + len) > PAGE_SIZE; + + /* + * Only two pages can be mapped at a time for writing. + */ + if (len + offset_in_page(addr) > 2 * PAGE_SIZE) + return -EINVAL; + /* + * Before reaching here, it was expected to lock the text_mutex + * already, so we don't need to give another lock here and could + * ensure that it was safe between each cores. + */ + lockdep_assert_held(&text_mutex); + + if (across_pages) + patch_map(addr + PAGE_SIZE, FIX_TEXT_POKE1); + + waddr = patch_map(addr, FIX_TEXT_POKE0); + + memset(waddr, c, len); + + patch_unmap(FIX_TEXT_POKE0); + + if (across_pages) + patch_unmap(FIX_TEXT_POKE1); + + return 0; +} +NOKPROBE_SYMBOL(__patch_insn_set); + static int __patch_insn_write(void *addr, const void *insn, size_t len) { void *waddr = addr; @@ -95,6 +129,14 @@ static int __patch_insn_write(void *addr, const void *insn, size_t len) } NOKPROBE_SYMBOL(__patch_insn_write); #else +static int __patch_insn_set(void *addr, u8 c, size_t len) +{ + memset(addr, c, len); + + return 0; +} +NOKPROBE_SYMBOL(__patch_insn_set); + static int __patch_insn_write(void *addr, const void *insn, size_t len) { return copy_to_kernel_nofault(addr, insn, len); @@ -102,6 +144,41 @@ static int __patch_insn_write(void *addr, const void *insn, size_t len) NOKPROBE_SYMBOL(__patch_insn_write); #endif /* CONFIG_MMU */ +static int patch_insn_set(void *addr, u8 c, size_t len) +{ + size_t patched = 0; + size_t size; + int ret = 0; + + /* + * __patch_insn_set() can only work on 2 pages at a time so call it in a + * loop with len <= 2 * PAGE_SIZE. + */ + while (patched < len && !ret) { + size = min_t(size_t, PAGE_SIZE * 2 - offset_in_page(addr + patched), len - patched); + ret = __patch_insn_set(addr + patched, c, size); + + patched += size; + } + + return ret; +} +NOKPROBE_SYMBOL(patch_insn_set); + +int patch_text_set_nosync(void *addr, u8 c, size_t len) +{ + u32 *tp = addr; + int ret; + + ret = patch_insn_set(tp, c, len); + + if (!ret) + flush_icache_range((uintptr_t)tp, (uintptr_t)tp + len); + + return ret; +} +NOKPROBE_SYMBOL(patch_text_set_nosync); + static int patch_insn_write(void *addr, const void *insn, size_t len) { size_t patched = 0;
The BPF JIT needs to write invalid instructions to RX regions of memory to invalidate removed BPF programs. This needs a function like memset() that can work with RX memory. Implement patch_text_set_nosync() which is similar to text_poke_set() of x86. Signed-off-by: Puranjay Mohan <puranjay12@gmail.com> --- arch/riscv/include/asm/patch.h | 1 + arch/riscv/kernel/patch.c | 77 ++++++++++++++++++++++++++++++++++ 2 files changed, 78 insertions(+)