[Lldb-commits] [lldb] [LLDB][LoongArch] Extend the maximum number of watchpoints (PR #126204)

[Tiezhu Yang via lldb-commits]

https://github.com/seehearfeel created 
https://github.com/llvm/llvm-project/pull/126204

The maximum number of load/store watchpoints and fetch instruction
watchpoints is 14 each according to LoongArch Reference Manual [1],
so extend the maximum number of watchpoints from 8 to 14 for ptrace.

A new struct user_watch_state_v2 was added into uapi in the related
kernel commit 531936dee53e ("LoongArch: Extend the maximum number of
watchpoints") [2], but there may be no struct user_watch_state_v2 in
the system header in time.

In order to avoid undefined or redefined error, just add a new struct
loongarch_user_watch_state in LLDB which is same with the uapi struct
user_watch_state_v2, then replace the current user_watch_state with
loongarch_user_watch_state.

As far as I can tell, the only users for this struct in the userspace
are GDB and LLDB, there are no any problems of software compatibility
between the application and kernel according to the analysis.

The compatibility problem has been considered while developing and
testing. When the applications in the userspace get watchpoint state,
the length will be specified which is no bigger than the sizeof struct
user_watch_state or user_watch_state_v2, the actual length is assigned
as the minimal value of the application and kernel in the generic code
of ptrace:

```
kernel/ptrace.c: ptrace_regset():

kiov->iov_len = min(kiov->iov_len,
(__kernel_size_t) (regset->n * regset->size));

if (req == PTRACE_GETREGSET)
return copy_regset_to_user(task, view, regset_no, 0,
   kiov->iov_len, kiov->iov_base);
else
return copy_regset_from_user(task, view, regset_no, 0,
 kiov->iov_len, kiov->iov_base);
```

For example, there are four kind of combinations, all of them work well.

(1) "older kernel + older app", the actual length is 8+(8+8+4+4)*8=200;
(2) "newer kernel + newer app", the actual length is 8+(8+8+4+4)*14=344;
(3) "older kernel + newer app", the actual length is 8+(8+8+4+4)*8=200;
(4) "newer kernel + older app", the actual length is 8+(8+8+4+4)*8=200.

Signed-off-by: Tiezhu Yang \

>From ee852ce4b316b16f7facab42fc3510f0a97242f1 Mon Sep 17 00:00:00 2001
From: Tiezhu Yang 
Date: Fri, 7 Feb 2025 12:09:30 +0800
Subject: [PATCH] [LLDB][LoongArch] Extend the maximum number of watchpoints

The maximum number of load/store watchpoints and fetch instruction
watchpoints is 14 each according to LoongArch Reference Manual [1],
so extend the maximum number of watchpoints from 8 to 14 for ptrace.

A new struct user_watch_state_v2 was added into uapi in the related
kernel commit 531936dee53e ("LoongArch: Extend the maximum number of
watchpoints") [2], but there may be no struct user_watch_state_v2 in
the system header in time.

In order to avoid undefined or redefined error, just add a new struct
loongarch_user_watch_state in LLDB which is same with the uapi struct
user_watch_state_v2, then replace the current user_watch_state with
loongarch_user_watch_state.

As far as I can tell, the only users for this struct in the userspace
are GDB and LLDB, there are no any problems of software compatibility
between the application and kernel according to the analysis.

The compatibility problem has been considered while developing and
testing. When the applications in the userspace get watchpoint state,
the length will be specified which is no bigger than the sizeof struct
user_watch_state or user_watch_state_v2, the actual length is assigned
as the minimal value of the application and kernel in the generic code
of ptrace:

```
kernel/ptrace.c: ptrace_regset():

kiov->iov_len = min(kiov->iov_len,
(__kernel_size_t) (regset->n * regset->size));

if (req == PTRACE_GETREGSET)
return copy_regset_to_user(task, view, regset_no, 0,
   kiov->iov_len, kiov->iov_base);
else
return copy_regset_from_user(task, view, regset_no, 0,
 kiov->iov_len, kiov->iov_base);
```

For example, there are four kind of combinations, all of them work well.

(1) "older kernel + older app", the actual length is 8+(8+8+4+4)*8=200;
(2) "newer kernel + newer app", the actual length is 8+(8+8+4+4)*14=344;
(3) "older kernel + newer app", the actual length is 8+(8+8+4+4)*8=200;
(4) "newer kernel + older app", the actual length is 8+(8+8+4+4)*8=200.

Signed-off-by: Tiezhu Yang 
---
 .../NativeRegisterContextLinux_loongarch64.cpp  | 17 +++--
 1 file changed, 15 insertions(+), 2 deletions(-)

diff --git 
a/lldb/source/Plugins/Process/Linux/NativeRegisterContextLinux_loongarch64.cpp 
b/lldb/source/Plugins/Process/Linux/NativeRegisterContextLinux_loongarch64.cpp
index 601dde250094892..c197da595b984f2 100644
--- 
a/lldb/source/Plugins/Process/Linux/NativeRegisterContextLinux_loongarch64.c

[Lldb-commits] [lldb] [LLDB][LoongArch] Extend the maximum number of watchpoints (PR #126204)

[Tiezhu Yang via lldb-commits]

https://github.com/seehearfeel updated 
https://github.com/llvm/llvm-project/pull/126204

>From 7f23aaea0abeafd408fbdd06f1b1a5393860af3a Mon Sep 17 00:00:00 2001
From: Tiezhu Yang 
Date: Fri, 7 Feb 2025 12:09:30 +0800
Subject: [PATCH] [LLDB][LoongArch] Extend the maximum number of watchpoints

The maximum number of load/store watchpoints and fetch instruction
watchpoints is 14 each according to LoongArch Reference Manual [1],
so extend the maximum number of watchpoints from 8 to 14 for ptrace.

A new struct user_watch_state_v2 was added into uapi in the related
kernel commit 531936dee53e ("LoongArch: Extend the maximum number of
watchpoints") [2], but there may be no struct user_watch_state_v2 in
the system header in time.

In order to avoid undefined or redefined error, just add a new struct
loongarch_user_watch_state in LLDB which is same with the uapi struct
user_watch_state_v2, then replace the current user_watch_state with
loongarch_user_watch_state.

As far as I can tell, the only users for this struct in the userspace
are GDB and LLDB, there are no any problems of software compatibility
between the application and kernel according to the analysis.

The compatibility problem has been considered while developing and
testing. When the applications in the userspace get watchpoint state,
the length will be specified which is no bigger than the sizeof struct
user_watch_state or user_watch_state_v2, the actual length is assigned
as the minimal value of the application and kernel in the generic code
of ptrace:

```
kernel/ptrace.c: ptrace_regset():

kiov->iov_len = min(kiov->iov_len,
(__kernel_size_t) (regset->n * regset->size));

if (req == PTRACE_GETREGSET)
return copy_regset_to_user(task, view, regset_no, 0,
   kiov->iov_len, kiov->iov_base);
else
return copy_regset_from_user(task, view, regset_no, 0,
 kiov->iov_len, kiov->iov_base);
```

For example, there are four kind of combinations, all of them work well.

(1) "older kernel + older app", the actual length is 8+(8+8+4+4)*8=200;
(2) "newer kernel + newer app", the actual length is 8+(8+8+4+4)*14=344;
(3) "older kernel + newer app", the actual length is 8+(8+8+4+4)*8=200;
(4) "newer kernel + older app", the actual length is 8+(8+8+4+4)*8=200.

[1] 
https://loongson.github.io/LoongArch-Documentation/LoongArch-Vol1-EN.html#control-and-status-registers-related-to-watchpoints
[2] 
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=531936dee53e

Signed-off-by: Tiezhu Yang 
---
 .../NativeRegisterContextLinux_loongarch64.cpp  | 17 +++--
 1 file changed, 15 insertions(+), 2 deletions(-)

diff --git 
a/lldb/source/Plugins/Process/Linux/NativeRegisterContextLinux_loongarch64.cpp 
b/lldb/source/Plugins/Process/Linux/NativeRegisterContextLinux_loongarch64.cpp
index 601dde250094892..c197da595b984f2 100644
--- 
a/lldb/source/Plugins/Process/Linux/NativeRegisterContextLinux_loongarch64.cpp
+++ 
b/lldb/source/Plugins/Process/Linux/NativeRegisterContextLinux_loongarch64.cpp
@@ -50,6 +50,19 @@
 #define REG_CONTEXT_SIZE   
\
   (GetGPRSize() + GetFPRSize() + sizeof(m_lsx) + sizeof(m_lasx))
 
+// In order to avoid undefined or redefined error, just add a new struct
+// loongarch_user_watch_state in LLDB which is same with the uapi struct
+// user_watch_state_v2.
+struct loongarch_user_watch_state {
+  uint64_t dbg_info;
+  struct {
+uint64_t addr;
+uint64_t mask;
+uint32_t ctrl;
+uint32_t pad;
+  } dbg_regs[14];
+};
+
 using namespace lldb;
 using namespace lldb_private;
 using namespace lldb_private::process_linux;
@@ -539,7 +552,7 @@ llvm::Error 
NativeRegisterContextLinux_loongarch64::ReadHardwareDebugInfo() {
 
   int regset = NT_LOONGARCH_HW_WATCH;
   struct iovec ioVec;
-  struct user_watch_state dreg_state;
+  struct loongarch_user_watch_state dreg_state;
   Status error;
 
   ioVec.iov_base = &dreg_state;
@@ -567,7 +580,7 @@ llvm::Error 
NativeRegisterContextLinux_loongarch64::ReadHardwareDebugInfo() {
 llvm::Error NativeRegisterContextLinux_loongarch64::WriteHardwareDebugRegs(
 DREGType hwbType) {
   struct iovec ioVec;
-  struct user_watch_state dreg_state;
+  struct loongarch_user_watch_state dreg_state;
   int regset;
 
   memset(&dreg_state, 0, sizeof(dreg_state));

___
lldb-commits mailing list
lldb-commits@lists.llvm.org
https://lists.llvm.org/cgi-bin/mailman/listinfo/lldb-commits

[Lldb-commits] [lldb] [LLDB][LoongArch] Extend the maximum number of watchpoints (PR #126204)

[Tiezhu Yang via lldb-commits]

https://github.com/seehearfeel edited 
https://github.com/llvm/llvm-project/pull/126204
___
lldb-commits mailing list
lldb-commits@lists.llvm.org
https://lists.llvm.org/cgi-bin/mailman/listinfo/lldb-commits

[Lldb-commits] [lldb] [LLDB][LoongArch] Extend the maximum number of watchpoints (PR #126204)

[Tiezhu Yang via lldb-commits]

@@ -50,6 +50,19 @@
 #define REG_CONTEXT_SIZE   
\
   (GetGPRSize() + GetFPRSize() + sizeof(m_lsx) + sizeof(m_lasx))
 
+// In order to avoid undefined or redefined error, just add a new struct
+// loongarch_user_watch_state in LLDB which is same with the uapi struct
+// user_watch_state_v2.

seehearfeel wrote:

OK, let me update it.

https://github.com/llvm/llvm-project/pull/126204
___
lldb-commits mailing list
lldb-commits@lists.llvm.org
https://lists.llvm.org/cgi-bin/mailman/listinfo/lldb-commits

[Lldb-commits] [lldb] [LLDB][LoongArch] Extend the maximum number of watchpoints (PR #126204)

[Tiezhu Yang via lldb-commits]

https://github.com/seehearfeel updated 
https://github.com/llvm/llvm-project/pull/126204

>From d813d794f15b66f9f2036692cc99c241a365046d Mon Sep 17 00:00:00 2001
From: Tiezhu Yang 
Date: Fri, 7 Feb 2025 12:09:30 +0800
Subject: [PATCH] [LLDB][LoongArch] Extend the maximum number of watchpoints

The maximum number of load/store watchpoints and fetch instruction
watchpoints is 14 each according to LoongArch Reference Manual [1],
so extend the maximum number of watchpoints from 8 to 14 for ptrace.

A new struct user_watch_state_v2 was added into uapi in the related
kernel commit 531936dee53e ("LoongArch: Extend the maximum number of
watchpoints") [2], but there may be no struct user_watch_state_v2 in
the system header in time.

In order to avoid undefined or redefined error, just add a new struct
loongarch_user_watch_state in LLDB which is same with the uapi struct
user_watch_state_v2, then replace the current user_watch_state with
loongarch_user_watch_state.

As far as I can tell, the only users for this struct in the userspace
are GDB and LLDB, there are no any problems of software compatibility
between the application and kernel according to the analysis.

The compatibility problem has been considered while developing and
testing. When the applications in the userspace get watchpoint state,
the length will be specified which is no bigger than the sizeof struct
user_watch_state or user_watch_state_v2, the actual length is assigned
as the minimal value of the application and kernel in the generic code
of ptrace:

```
kernel/ptrace.c: ptrace_regset():

kiov->iov_len = min(kiov->iov_len,
(__kernel_size_t) (regset->n * regset->size));

if (req == PTRACE_GETREGSET)
return copy_regset_to_user(task, view, regset_no, 0,
   kiov->iov_len, kiov->iov_base);
else
return copy_regset_from_user(task, view, regset_no, 0,
 kiov->iov_len, kiov->iov_base);
```

For example, there are four kind of combinations, all of them work well.

(1) "older kernel + older app", the actual length is 8+(8+8+4+4)*8=200;
(2) "newer kernel + newer app", the actual length is 8+(8+8+4+4)*14=344;
(3) "older kernel + newer app", the actual length is 8+(8+8+4+4)*8=200;
(4) "newer kernel + older app", the actual length is 8+(8+8+4+4)*8=200.

[1] 
https://loongson.github.io/LoongArch-Documentation/LoongArch-Vol1-EN.html#control-and-status-registers-related-to-watchpoints
[2] 
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=531936dee53e

Signed-off-by: Tiezhu Yang 
---
 ...NativeRegisterContextLinux_loongarch64.cpp | 21 +--
 1 file changed, 19 insertions(+), 2 deletions(-)

diff --git 
a/lldb/source/Plugins/Process/Linux/NativeRegisterContextLinux_loongarch64.cpp 
b/lldb/source/Plugins/Process/Linux/NativeRegisterContextLinux_loongarch64.cpp
index 601dde250094892..c4841950f1e07c9 100644
--- 
a/lldb/source/Plugins/Process/Linux/NativeRegisterContextLinux_loongarch64.cpp
+++ 
b/lldb/source/Plugins/Process/Linux/NativeRegisterContextLinux_loongarch64.cpp
@@ -50,6 +50,23 @@
 #define REG_CONTEXT_SIZE   
\
   (GetGPRSize() + GetFPRSize() + sizeof(m_lsx) + sizeof(m_lasx))
 
+// ptrace has a struct type user_watch_state, which was replaced by
+// user_watch_state_v2 when more watchpoints were added, so this file
+// may be built on systems with one or both in the system headers.
+// The type below has the same layout as user_watch_state_v2 but will
+// not clash with that name if it exists. We can use the v2 layout even
+// on old kernels as we will only see 8 watchpoints and the kernel will
+// truncate any extra data we send to it.
+struct loongarch_user_watch_state {
+  uint64_t dbg_info;
+  struct {
+uint64_t addr;
+uint64_t mask;
+uint32_t ctrl;
+uint32_t pad;
+  } dbg_regs[14];
+};
+
 using namespace lldb;
 using namespace lldb_private;
 using namespace lldb_private::process_linux;
@@ -539,7 +556,7 @@ llvm::Error 
NativeRegisterContextLinux_loongarch64::ReadHardwareDebugInfo() {
 
   int regset = NT_LOONGARCH_HW_WATCH;
   struct iovec ioVec;
-  struct user_watch_state dreg_state;
+  struct loongarch_user_watch_state dreg_state;
   Status error;
 
   ioVec.iov_base = &dreg_state;
@@ -567,7 +584,7 @@ llvm::Error 
NativeRegisterContextLinux_loongarch64::ReadHardwareDebugInfo() {
 llvm::Error NativeRegisterContextLinux_loongarch64::WriteHardwareDebugRegs(
 DREGType hwbType) {
   struct iovec ioVec;
-  struct user_watch_state dreg_state;
+  struct loongarch_user_watch_state dreg_state;
   int regset;
 
   memset(&dreg_state, 0, sizeof(dreg_state));

___
lldb-commits mailing list
lldb-commits@lists.llvm.org
https://lists.llvm.org/cgi-bin/mailman/listinfo/lldb-commits

[Lldb-commits] [lldb] [LLDB][LoongArch] Fix build errors about NT_LOONGARCH_HW_{BREAK, WATCH} (PR #126020)

[Tiezhu Yang via lldb-commits]

seehearfeel wrote:

By now, the format of pr and patch seem no problems, but my email setting of 
GitHub is not correct, I will update the comment
once it is OK, please wait some time before merging it, thank you.

https://github.com/llvm/llvm-project/pull/126020
___
lldb-commits mailing list
lldb-commits@lists.llvm.org
https://lists.llvm.org/cgi-bin/mailman/listinfo/lldb-commits

[Lldb-commits] [lldb] [LLDB][LoongArch] Fix build errors about NT_LOONGARCH_HW_{BREAK, WATCH} (PR #126020)

[Tiezhu Yang via lldb-commits]

https://github.com/seehearfeel updated 
https://github.com/llvm/llvm-project/pull/126020

>From 7adde90f84cd43fe47c30a094a483b68fafe9bef Mon Sep 17 00:00:00 2001
From: Tiezhu Yang 
Date: Thu, 23 Jan 2025 15:30:20 +0800
Subject: [PATCH] [LLDB][LoongArch] Fix build errors about
 NT_LOONGARCH_HW_{BREAK,WATCH}

On some OS distros such as LoongArch Fedora 38 mate-5 [1], there are
no macro definitions NT_LOONGARCH_HW_BREAK and NT_LOONGARCH_HW_WATCH
in the system header, then there exist some errors when building LLDB
on LoongArch.

(1) Description of Problem:

llvm-project/lldb/source/Plugins/Process/Linux/NativeRegisterContextLinux_loongarch64.cpp:529:16:
error: 'NT_LOONGARCH_HW_WATCH' was not declared in this scope; did you mean 
'NT_LOONGARCH_LBT'?
  529 |   int regset = NT_LOONGARCH_HW_WATCH;
  |^
  |NT_LOONGARCH_LBT
llvm-project/lldb/source/Plugins/Process/Linux/NativeRegisterContextLinux_loongarch64.cpp:543:12:
error: 'NT_LOONGARCH_HW_BREAK' was not declared in this scope; did you mean 
'NT_LOONGARCH_CSR'?
  543 |   regset = NT_LOONGARCH_HW_BREAK;
  |^
  |NT_LOONGARCH_CSR

(2) Steps to Reproduce:

git clone https://github.com/llvm/llvm-project.git
mkdir -p llvm-project/llvm/build && cd llvm-project/llvm/build
cmake .. -G "Ninja" \
 -DCMAKE_BUILD_TYPE=Release \
 -DLLVM_BUILD_RUNTIME=OFF \
 -DLLVM_ENABLE_PROJECTS="clang;lldb" \
 -DCMAKE_INSTALL_PREFIX=/usr/local/llvm \
 -DLLVM_TARGETS_TO_BUILD="LoongArch" \
 -DLLVM_HOST_TRIPLE=loongarch64-redhat-linux
ninja

(3) Additional Info:

Maybe there are no problems on the OS distros with newer glibc devel
library, so this issue is related with OS distros.

(4) Root Cause Analysis:

This is because the related Linux kernel commit [2] was merged in
2023-02-25 and the glibc devel library has some delay with kernel,
the glibc version of specified OS distros is not updated in time.

(5) Final Solution:

One way is to ask the maintainer of OS distros to update glibc devel
library, but it is better to not depend on the glibc version.

In order to avoid the build errors, just define NT_LOONGARCH_HW_BREAK
and NT_LOONGARCH_HW_WATCH in LLDB if there are no these definitions in
the system header.

By the way, in order to fit within 80 columns, use C++-style comments
for the new added NT_LOONGARCH_HW_BREAK and NT_LOONGARCH_HW_WATCH.

While at it, for consistency, just modify the current NT_LOONGARCH_LSX
and NT_LOONGARCH_LASX to C++-style comments too.

[1] 
https://mirrors.wsyu.edu.cn/fedora/linux/development/rawhide/Everything/loongarch64/iso/livecd-fedora-mate-5.loongarch64.iso
[2] 
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=1a69f7a161a7

Signed-off-by: Tiezhu Yang 
---
 .../NativeRegisterContextLinux_loongarch64.cpp  | 17 ++---
 1 file changed, 14 insertions(+), 3 deletions(-)

diff --git 
a/lldb/source/Plugins/Process/Linux/NativeRegisterContextLinux_loongarch64.cpp 
b/lldb/source/Plugins/Process/Linux/NativeRegisterContextLinux_loongarch64.cpp
index b04018ee243fd7d..601dde250094892 100644
--- 
a/lldb/source/Plugins/Process/Linux/NativeRegisterContextLinux_loongarch64.cpp
+++ 
b/lldb/source/Plugins/Process/Linux/NativeRegisterContextLinux_loongarch64.cpp
@@ -27,13 +27,24 @@
 // struct iovec definition
 #include 
 
+// LoongArch SIMD eXtension registers
 #ifndef NT_LOONGARCH_LSX
-#define NT_LOONGARCH_LSX 0xa02 /* LoongArch SIMD eXtension registers */
+#define NT_LOONGARCH_LSX 0xa02
 #endif
 
+// LoongArch Advanced SIMD eXtension registers
 #ifndef NT_LOONGARCH_LASX
-#define NT_LOONGARCH_LASX  
\
-  0xa03 /* LoongArch Advanced SIMD eXtension registers */
+#define NT_LOONGARCH_LASX 0xa03
+#endif
+
+// LoongArch hardware breakpoint registers
+#ifndef NT_LOONGARCH_HW_BREAK
+#define NT_LOONGARCH_HW_BREAK 0xa05
+#endif
+
+// LoongArch hardware watchpoint registers
+#ifndef NT_LOONGARCH_HW_WATCH
+#define NT_LOONGARCH_HW_WATCH 0xa06
 #endif
 
 #define REG_CONTEXT_SIZE   
\

___
lldb-commits mailing list
lldb-commits@lists.llvm.org
https://lists.llvm.org/cgi-bin/mailman/listinfo/lldb-commits

[Lldb-commits] [lldb] [LLDB][LoongArch] Fix build errors about NT_LOONGARCH_HW_{BREAK, WATCH} (PR #126020)

[Tiezhu Yang via lldb-commits]

https://github.com/seehearfeel edited 
https://github.com/llvm/llvm-project/pull/126020
___
lldb-commits mailing list
lldb-commits@lists.llvm.org
https://lists.llvm.org/cgi-bin/mailman/listinfo/lldb-commits