diff mbox series

[bpf-next,v2,2/3] riscv: implement a memset like function for text

Message ID 20230824133135.1176709-3-puranjay12@gmail.com (mailing list archive)
State Superseded
Delegated to: BPF
Headers show
Series bpf, riscv: use BPF prog pack allocator in BPF JIT | expand

Checks

Context Check Description
bpf/vmtest-bpf-next-VM_Test-8 success Logs for test_maps on x86_64 with gcc
bpf/vmtest-bpf-next-VM_Test-9 success Logs for test_maps on x86_64 with llvm-16
bpf/vmtest-bpf-next-VM_Test-14 success Logs for test_progs_no_alu32 on aarch64 with gcc
bpf/vmtest-bpf-next-VM_Test-10 success Logs for test_progs on aarch64 with gcc
bpf/vmtest-bpf-next-VM_Test-21 success Logs for test_progs_parallel on aarch64 with gcc
bpf/vmtest-bpf-next-VM_Test-19 success Logs for test_progs_no_alu32_parallel on x86_64 with gcc
bpf/vmtest-bpf-next-VM_Test-13 success Logs for test_progs on x86_64 with llvm-16
bpf/vmtest-bpf-next-VM_Test-12 success Logs for test_progs on x86_64 with gcc
bpf/vmtest-bpf-next-VM_Test-18 success Logs for test_progs_no_alu32_parallel on aarch64 with gcc
bpf/vmtest-bpf-next-VM_Test-16 success Logs for test_progs_no_alu32 on x86_64 with gcc
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bpf/vmtest-bpf-next-VM_Test-20 success Logs for test_progs_no_alu32_parallel on x86_64 with llvm-16
bpf/vmtest-bpf-next-VM_Test-27 success Logs for test_verifier on x86_64 with llvm-16
bpf/vmtest-bpf-next-VM_Test-26 success Logs for test_verifier on x86_64 with gcc
bpf/vmtest-bpf-next-VM_Test-28 success Logs for veristat
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bpf/vmtest-bpf-next-VM_Test-24 success Logs for test_verifier on aarch64 with gcc
bpf/vmtest-bpf-next-VM_Test-25 success Logs for test_verifier on s390x with gcc
bpf/vmtest-bpf-next-VM_Test-15 success Logs for test_progs_no_alu32 on s390x with gcc
bpf/vmtest-bpf-next-VM_Test-11 success Logs for test_progs on s390x with gcc
netdev/series_format success Posting correctly formatted
netdev/tree_selection success Clearly marked for bpf-next, async
netdev/fixes_present success Fixes tag not required for -next series
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 9 this patch: 9
netdev/cc_maintainers warning 1 maintainers not CCed: bjorn@rivosinc.com
netdev/build_clang success Errors and warnings before: 9 this patch: 9
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/deprecated_api success None detected
netdev/check_selftest success No net selftest shell script
netdev/verify_fixes success No Fixes tag
netdev/build_allmodconfig_warn success Errors and warnings before: 9 this patch: 9
netdev/checkpatch warning CHECK: Consider using #include <linux/string.h> instead of <asm/string.h> CHECK: No space is necessary after a cast CHECK: Please use a blank line after function/struct/union/enum declarations WARNING: space prohibited between function name and open parenthesis '('
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0
bpf/vmtest-bpf-next-VM_Test-0 success Logs for ${{ matrix.test }} on ${{ matrix.arch }} with ${{ matrix.toolchain_full }}
bpf/vmtest-bpf-next-VM_Test-3 fail Logs for build for s390x with gcc
bpf/vmtest-bpf-next-VM_Test-1 success Logs for ShellCheck
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bpf/vmtest-bpf-next-VM_Test-4 success Logs for build for x86_64 with gcc
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bpf/vmtest-bpf-next-PR fail PR summary
bpf/vmtest-bpf-next-VM_Test-7 success Logs for veristat

Commit Message

Puranjay Mohan Aug. 24, 2023, 1:31 p.m. UTC 
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      | 74 ++++++++++++++++++++++++++++++++++
 2 files changed, 75 insertions(+)

Comments

Song Liu Aug. 24, 2023, 10:05 p.m. UTC | #1 
On Thu, Aug 24, 2023 at 6:31 AM Puranjay Mohan <puranjay12@gmail.com> 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      | 74 ++++++++++++++++++++++++++++++++++
>  2 files changed, 75 insertions(+)
>
> diff --git a/arch/riscv/include/asm/patch.h b/arch/riscv/include/asm/patch.h
> index 63c98833d510..aa5c1830ea43 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, const int 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 465b2eebbc37..24d49999ac1a 100644
> --- a/arch/riscv/kernel/patch.c
> +++ b/arch/riscv/kernel/patch.c
> @@ -13,6 +13,7 @@
>  #include <asm/fixmap.h>
>  #include <asm/ftrace.h>
>  #include <asm/patch.h>
> +#include <asm/string.h>
>
>  struct patch_insn {
>         void *addr;
> @@ -53,6 +54,34 @@ static void patch_unmap(int fixmap)
>  }
>  NOKPROBE_SYMBOL(patch_unmap);
>
> +static int __patch_insn_set(void *addr, const int c, size_t len)
> +{
> +       void *waddr = addr;
> +       bool across_pages = (((uintptr_t) addr & ~PAGE_MASK) + len) > PAGE_SIZE;
> +       int ret;
> +
> +       /*
> +        * Only two pages can be mapped at a time for writing.
> +        */
> +       if (len > 2 * PAGE_SIZE)
> +               return -EINVAL;

Same for this one.

[...]
kernel test robot Aug. 25, 2023, 1:26 a.m. UTC | #2 
Hi Puranjay,

kernel test robot noticed the following build warnings:

[auto build test WARNING on bpf-next/master]

url:    https://github.com/intel-lab-lkp/linux/commits/Puranjay-Mohan/riscv-extend-patch_text_nosync-for-multiple-pages/20230824-213410
base:   https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next.git master
patch link:    https://lore.kernel.org/r/20230824133135.1176709-3-puranjay12%40gmail.com
patch subject: [PATCH bpf-next v2 2/3] riscv: implement a memset like function for text
config: riscv-allnoconfig (https://download.01.org/0day-ci/archive/20230825/202308250924.NlFcBoND-lkp@intel.com/config)
compiler: riscv64-linux-gcc (GCC) 13.2.0
reproduce: (https://download.01.org/0day-ci/archive/20230825/202308250924.NlFcBoND-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202308250924.NlFcBoND-lkp@intel.com/

All warnings (new ones prefixed by >>):

   arch/riscv/kernel/patch.c: In function '__patch_insn_set':
>> arch/riscv/kernel/patch.c:61:13: warning: unused variable 'ret' [-Wunused-variable]
      61 |         int ret;
         |             ^~~


vim +/ret +61 arch/riscv/kernel/patch.c

    56	
    57	static int __patch_insn_set(void *addr, const int c, size_t len)
    58	{
    59		void *waddr = addr;
    60		bool across_pages = (((uintptr_t) addr & ~PAGE_MASK) + len) > PAGE_SIZE;
  > 61		int ret;
    62	
    63		/*
    64		 * Only two pages can be mapped at a time for writing.
    65		 */
    66		if (len > 2 * PAGE_SIZE)
    67			return -EINVAL;
    68	
    69		if (across_pages)
    70			patch_map(addr + PAGE_SIZE, FIX_TEXT_POKE1);
    71	
    72		waddr = patch_map(addr, FIX_TEXT_POKE0);
    73	
    74		memset(waddr, c, len);
    75	
    76		patch_unmap(FIX_TEXT_POKE0);
    77	
    78		if (across_pages)
    79			patch_unmap(FIX_TEXT_POKE1);
    80	
    81		return 0;
    82	}
    83	NOKPROBE_SYMBOL(__patch_insn_set);
    84
Pu Lehui Aug. 25, 2023, 7:59 a.m. UTC | #3 
On 2023/8/24 21:31, 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      | 74 ++++++++++++++++++++++++++++++++++
>   2 files changed, 75 insertions(+)
> 
> diff --git a/arch/riscv/include/asm/patch.h b/arch/riscv/include/asm/patch.h
> index 63c98833d510..aa5c1830ea43 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, const int 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 465b2eebbc37..24d49999ac1a 100644
> --- a/arch/riscv/kernel/patch.c
> +++ b/arch/riscv/kernel/patch.c
> @@ -13,6 +13,7 @@
>   #include <asm/fixmap.h>
>   #include <asm/ftrace.h>
>   #include <asm/patch.h>
> +#include <asm/string.h>
>   
>   struct patch_insn {
>   	void *addr;
> @@ -53,6 +54,34 @@ static void patch_unmap(int fixmap)
>   }
>   NOKPROBE_SYMBOL(patch_unmap);
>   
> +static int __patch_insn_set(void *addr, const int c, size_t len)
> +{
> +	void *waddr = addr;
> +	bool across_pages = (((uintptr_t) addr & ~PAGE_MASK) + len) > PAGE_SIZE;
> +	int ret;
> +
> +	/*
> +	 * Only two pages can be mapped at a time for writing.
> +	 */
> +	if (len > 2 * PAGE_SIZE)
> +		return -EINVAL;
> +

As a generic part, it better to add text_mutex lock assert.

> +	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 +124,14 @@ 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, const int 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 +139,43 @@ 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, const int 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, const int 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;
Björn Töpel Aug. 26, 2023, 2:02 p.m. UTC | #4 
Puranjay Mohan <puranjay12@gmail.com> writes:

> 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.

Some additional nits, in addition to the other comments (Song, kernel
test bot, Lehui).

> Signed-off-by: Puranjay Mohan <puranjay12@gmail.com>
> ---
>  arch/riscv/include/asm/patch.h |  1 +
>  arch/riscv/kernel/patch.c      | 74 ++++++++++++++++++++++++++++++++++
>  2 files changed, 75 insertions(+)
>
> diff --git a/arch/riscv/include/asm/patch.h b/arch/riscv/include/asm/patch.h
> index 63c98833d510..aa5c1830ea43 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, const int 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 465b2eebbc37..24d49999ac1a 100644
> --- a/arch/riscv/kernel/patch.c
> +++ b/arch/riscv/kernel/patch.c
> @@ -13,6 +13,7 @@
>  #include <asm/fixmap.h>
>  #include <asm/ftrace.h>
>  #include <asm/patch.h>
> +#include <asm/string.h>
>  
>  struct patch_insn {
>  	void *addr;
> @@ -53,6 +54,34 @@ static void patch_unmap(int fixmap)
>  }
>  NOKPROBE_SYMBOL(patch_unmap);
>  
> +static int __patch_insn_set(void *addr, const int c, size_t len)

Drop the "const" from "const int c" everywhere in this patch, and let's
just use u8 instead of int. We don't need to carry the old memset()
legacy argumentts! We're more modern than that! ;-)


Björn
diff mbox series

Patch

diff --git a/arch/riscv/include/asm/patch.h b/arch/riscv/include/asm/patch.h
index 63c98833d510..aa5c1830ea43 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, const int 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 465b2eebbc37..24d49999ac1a 100644
--- a/arch/riscv/kernel/patch.c
+++ b/arch/riscv/kernel/patch.c
@@ -13,6 +13,7 @@ 
 #include <asm/fixmap.h>
 #include <asm/ftrace.h>
 #include <asm/patch.h>
+#include <asm/string.h>
 
 struct patch_insn {
 	void *addr;
@@ -53,6 +54,34 @@  static void patch_unmap(int fixmap)
 }
 NOKPROBE_SYMBOL(patch_unmap);
 
+static int __patch_insn_set(void *addr, const int c, size_t len)
+{
+	void *waddr = addr;
+	bool across_pages = (((uintptr_t) addr & ~PAGE_MASK) + len) > PAGE_SIZE;
+	int ret;
+
+	/*
+	 * Only two pages can be mapped at a time for writing.
+	 */
+	if (len > 2 * PAGE_SIZE)
+		return -EINVAL;
+
+	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 +124,14 @@  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, const int 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 +139,43 @@  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, const int 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, const int 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;