scripts/gdb: update documentation for lx_per_cpu

Commit db08c53fdd ("scripts/gdb: fix parameter handling in
$lx_per_cpu") changed the parameter handling of lx_per_cpu to use GdbValue
instead of parsing the variable name.  Update the documentation to reflect
the new lx_per_cpu usage.  Update the hrtimer_bases example to use rb_tree
instead of the timerqueue_head.next pointer removed in commit
511885d706 ("lib/timerqueue: Rely on rbtree semantics for next
timer").

Link: https://lkml.kernel.org/r/20250503123234.2407184-3-illia@yshyn.com
Signed-off-by: Illia Ostapyshyn <illia@yshyn.com>
Cc: Alex Shi <alexs@kernel.org>
Cc: Brendan Jackman <jackmanb@google.com>
Cc: Dongliang Mu <dzm91@hust.edu.cn>
Cc: Florian Rommel <mail@florommel.de>
Cc: Hu Haowen <2023002089@link.tyut.edu.cn>
Cc: Jan Kiszka <jan.kiszka@siemens.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Kieran Bingham <kbingham@kernel.org>
Cc: Yanteng Si <si.yanteng@linux.dev>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Documentation/process/debugging/gdb-kernel-debugging.rst

@@ -127,35 +127,31 @@ Examples of using the Linux-provided gdb helpers
 
 - Make use of the per-cpu function for the current or a specified CPU::
 
-    (gdb) p $lx_per_cpu("runqueues").nr_running
+    (gdb) p $lx_per_cpu(runqueues).nr_running
     $3 = 1
-    (gdb) p $lx_per_cpu("runqueues", 2).nr_running
+    (gdb) p $lx_per_cpu(runqueues, 2).nr_running
     $4 = 0
 
 - Dig into hrtimers using the container_of helper::
 
-    (gdb) set $next = $lx_per_cpu("hrtimer_bases").clock_base[0].active.next
-    (gdb) p *$container_of($next, "struct hrtimer", "node")
+    (gdb) set $leftmost = $lx_per_cpu(hrtimer_bases).clock_base[0].active.rb_root.rb_leftmost
+    (gdb) p *$container_of($leftmost, "struct hrtimer", "node")
     $5 = {
       node = {
         node = {
-          __rb_parent_color = 18446612133355256072,
-          rb_right = 0x0 <irq_stack_union>,
-          rb_left = 0x0 <irq_stack_union>
+          __rb_parent_color = 18446612686384860673,
+          rb_right = 0xffff888231da8b00,
+          rb_left = 0x0
         },
-        expires = {
-          tv64 = 1835268000000
-        }
+        expires = 1228461000000
       },
-      _softexpires = {
-        tv64 = 1835268000000
-      },
-      function = 0xffffffff81078232 <tick_sched_timer>,
-      base = 0xffff88003fd0d6f0,
-      state = 1,
-      start_pid = 0,
-      start_site = 0xffffffff81055c1f <hrtimer_start_range_ns+20>,
-      start_comm = "swapper/2\000\000\000\000\000\000"
+      _softexpires = 1228461000000,
+      function = 0xffffffff8137ab20 <tick_nohz_handler>,
+      base = 0xffff888231d9b4c0,
+      state = 1 '\001',
+      is_rel = 0 '\000',
+      is_soft = 0 '\000',
+      is_hard = 1 '\001'
     }
 
 

Documentation/translations/zh_CN/dev-tools/gdb-kernel-debugging.rst

@@ -120,35 +120,31 @@ Kgdb内核调试器、QEMU等虚拟机管理程序或基于JTAG的硬件接口
 
 - 对当前或指定的CPU使用per-cpu函数::
 
-    (gdb) p $lx_per_cpu("runqueues").nr_running
+    (gdb) p $lx_per_cpu(runqueues).nr_running
     $3 = 1
-    (gdb) p $lx_per_cpu("runqueues", 2).nr_running
+    (gdb) p $lx_per_cpu(runqueues, 2).nr_running
     $4 = 0
 
 - 使用container_of查看更多hrtimers信息::
 
-    (gdb) set $next = $lx_per_cpu("hrtimer_bases").clock_base[0].active.next
-    (gdb) p *$container_of($next, "struct hrtimer", "node")
+    (gdb) set $leftmost = $lx_per_cpu(hrtimer_bases).clock_base[0].active.rb_root.rb_leftmost
+    (gdb) p *$container_of($leftmost, "struct hrtimer", "node")
     $5 = {
       node = {
         node = {
-          __rb_parent_color = 18446612133355256072,
-          rb_right = 0x0 <irq_stack_union>,
-          rb_left = 0x0 <irq_stack_union>
+          __rb_parent_color = 18446612686384860673,
+          rb_right = 0xffff888231da8b00,
+          rb_left = 0x0
         },
-        expires = {
-          tv64 = 1835268000000
-        }
+        expires = 1228461000000
       },
-      _softexpires = {
-        tv64 = 1835268000000
-      },
-      function = 0xffffffff81078232 <tick_sched_timer>,
-      base = 0xffff88003fd0d6f0,
-      state = 1,
-      start_pid = 0,
-      start_site = 0xffffffff81055c1f <hrtimer_start_range_ns+20>,
-      start_comm = "swapper/2\000\000\000\000\000\000"
+      _softexpires = 1228461000000,
+      function = 0xffffffff8137ab20 <tick_nohz_handler>,
+      base = 0xffff888231d9b4c0,
+      state = 1 '\001',
+      is_rel = 0 '\000',
+      is_soft = 0 '\000',
+      is_hard = 1 '\001'
     }
 
 

Documentation/translations/zh_TW/dev-tools/gdb-kernel-debugging.rst

@@ -116,35 +116,31 @@ Kgdb內核調試器、QEMU等虛擬機管理程序或基於JTAG的硬件接口
 
 - 對當前或指定的CPU使用per-cpu函數::
 
-    (gdb) p $lx_per_cpu("runqueues").nr_running
+    (gdb) p $lx_per_cpu(runqueues).nr_running
     $3 = 1
-    (gdb) p $lx_per_cpu("runqueues", 2).nr_running
+    (gdb) p $lx_per_cpu(runqueues, 2).nr_running
     $4 = 0
 
 - 使用container_of查看更多hrtimers信息::
 
-    (gdb) set $next = $lx_per_cpu("hrtimer_bases").clock_base[0].active.next
-    (gdb) p *$container_of($next, "struct hrtimer", "node")
+    (gdb) set $leftmost = $lx_per_cpu(hrtimer_bases).clock_base[0].active.rb_root.rb_leftmost
+    (gdb) p *$container_of($leftmost, "struct hrtimer", "node")
     $5 = {
       node = {
         node = {
-          __rb_parent_color = 18446612133355256072,
-          rb_right = 0x0 <irq_stack_union>,
-          rb_left = 0x0 <irq_stack_union>
+          __rb_parent_color = 18446612686384860673,
+          rb_right = 0xffff888231da8b00,
+          rb_left = 0x0
         },
-        expires = {
-          tv64 = 1835268000000
-        }
+        expires = 1228461000000
       },
-      _softexpires = {
-        tv64 = 1835268000000
-      },
-      function = 0xffffffff81078232 <tick_sched_timer>,
-      base = 0xffff88003fd0d6f0,
-      state = 1,
-      start_pid = 0,
-      start_site = 0xffffffff81055c1f <hrtimer_start_range_ns+20>,
-      start_comm = "swapper/2\000\000\000\000\000\000"
+      _softexpires = 1228461000000,
+      function = 0xffffffff8137ab20 <tick_nohz_handler>,
+      base = 0xffff888231d9b4c0,
+      state = 1 '\001',
+      is_rel = 0 '\000',
+      is_soft = 0 '\000',
+      is_hard = 1 '\001'
     }
 
 

scripts/gdb/linux/cpus.py

@@ -141,7 +141,7 @@ LxCpus()
 class PerCpu(gdb.Function):
     """Return per-cpu variable.
 
-$lx_per_cpu("VAR"[, CPU]): Return the per-cpu variable called VAR for the
+$lx_per_cpu(VAR[, CPU]): Return the per-cpu variable called VAR for the
 given CPU number. If CPU is omitted, the CPU of the current context is used.
 Note that VAR has to be quoted as string."""
 
@@ -158,7 +158,7 @@ PerCpu()
 class PerCpuPtr(gdb.Function):
     """Return per-cpu pointer.
 
-$lx_per_cpu_ptr("VAR"[, CPU]): Return the per-cpu pointer called VAR for the
+$lx_per_cpu_ptr(VAR[, CPU]): Return the per-cpu pointer called VAR for the
 given CPU number. If CPU is omitted, the CPU of the current context is used.
 Note that VAR has to be quoted as string."""