linux.git/arch/riscv/kernel/Makefile, branch v5.14 Linux kernel source tree riscv: kexec: do not add '-mno-relax' flag if compiler doesn't support it 2021-08-12T14:16:52+00:00 Changbin Du changbin.du@gmail.com 2021-07-22T02:17:15+00:00 030d6dbf0c2e5fdf23ad29557f0c87a882993e26 The RISC-V special option '-mno-relax' which to disable linker relaxations is supported by GCC8+. For GCC7 and lower versions do not support this option. Fixes: fba8a8674f68 ("RISC-V: Add kexec support") Signed-off-by: Changbin Du <changbin.du@gmail.com> Cc: stable@vger.kernel.org Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com> 
The RISC-V special option '-mno-relax' which to disable linker relaxations
is supported by GCC8+. For GCC7 and lower versions do not support this
option.

Fixes: fba8a8674f68 ("RISC-V: Add kexec support")
Signed-off-by: Changbin Du <changbin.du@gmail.com>
Cc: stable@vger.kernel.org
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
Merge tag 'riscv-for-linus-5.13-mw0' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux 2021-05-06T16:24:18+00:00 Linus Torvalds torvalds@linux-foundation.org 2021-05-06T16:24:18+00:00 939b7cbc00906b02c6eae6a380ad6c24c7a1e043 Pull RISC-V updates from Palmer Dabbelt: - Support for the memtest= kernel command-line argument. - Support for building the kernel with FORTIFY_SOURCE. - Support for generic clockevent broadcasts. - Support for the buildtar build target. - Some build system cleanups to pass more LLVM-friendly arguments. - Support for kprobes. - A rearranged kernel memory map, the first part of supporting sv48 systems. - Improvements to kexec, along with support for kdump and crash kernels. - An alternatives-based errata framework, along with support for handling a pair of errata that manifest on some SiFive designs (including the HiFive Unmatched). - Support for XIP. - A device tree for the Microchip PolarFire ICICLE SoC and associated dev board. ... along with a bunch of cleanups. There are already a handful of fixes on the list so there will likely be a part 2. * tag 'riscv-for-linus-5.13-mw0' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux: (45 commits) RISC-V: Always define XIP_FIXUP riscv: Remove 32b kernel mapping from page table dump riscv: Fix 32b kernel build with CONFIG_DEBUG_VIRTUAL=y RISC-V: Fix error code returned by riscv_hartid_to_cpuid() RISC-V: Enable Microchip PolarFire ICICLE SoC RISC-V: Initial DTS for Microchip ICICLE board dt-bindings: riscv: microchip: Add YAML documentation for the PolarFire SoC RISC-V: Add Microchip PolarFire SoC kconfig option RISC-V: enable XIP RISC-V: Add crash kernel support RISC-V: Add kdump support RISC-V: Improve init_resources() RISC-V: Add kexec support RISC-V: Add EM_RISCV to kexec UAPI header riscv: vdso: fix and clean-up Makefile riscv/mm: Use BUG_ON instead of if condition followed by BUG. riscv/kprobe: fix kernel panic when invoking sys_read traced by kprobe riscv: Set ARCH_HAS_STRICT_MODULE_RWX if MMU riscv: module: Create module allocations without exec permissions riscv: bpf: Avoid breaking W^X ... 
Pull RISC-V updates from Palmer Dabbelt:

 - Support for the memtest= kernel command-line argument.

 - Support for building the kernel with FORTIFY_SOURCE.

 - Support for generic clockevent broadcasts.

 - Support for the buildtar build target.

 - Some build system cleanups to pass more LLVM-friendly arguments.

 - Support for kprobes.

 - A rearranged kernel memory map, the first part of supporting sv48
   systems.

 - Improvements to kexec, along with support for kdump and crash
   kernels.

 - An alternatives-based errata framework, along with support for
   handling a pair of errata that manifest on some SiFive designs
   (including the HiFive Unmatched).

 - Support for XIP.

 - A device tree for the Microchip PolarFire ICICLE SoC and associated
   dev board.

... along with a bunch of cleanups.  There are already a handful of fixes
on the list so there will likely be a part 2.

* tag 'riscv-for-linus-5.13-mw0' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux: (45 commits)
  RISC-V: Always define XIP_FIXUP
  riscv: Remove 32b kernel mapping from page table dump
  riscv: Fix 32b kernel build with CONFIG_DEBUG_VIRTUAL=y
  RISC-V: Fix error code returned by riscv_hartid_to_cpuid()
  RISC-V: Enable Microchip PolarFire ICICLE SoC
  RISC-V: Initial DTS for Microchip ICICLE board
  dt-bindings: riscv: microchip: Add YAML documentation for the PolarFire SoC
  RISC-V: Add Microchip PolarFire SoC kconfig option
  RISC-V: enable XIP
  RISC-V: Add crash kernel support
  RISC-V: Add kdump support
  RISC-V: Improve init_resources()
  RISC-V: Add kexec support
  RISC-V: Add EM_RISCV to kexec UAPI header
  riscv: vdso: fix and clean-up Makefile
  riscv/mm: Use BUG_ON instead of if condition followed by BUG.
  riscv/kprobe: fix kernel panic when invoking sys_read traced by kprobe
  riscv: Set ARCH_HAS_STRICT_MODULE_RWX if MMU
  riscv: module: Create module allocations without exec permissions
  riscv: bpf: Avoid breaking W^X
  ...
RISC-V: Add crash kernel support 2021-04-26T15:25:24+00:00 Nick Kossifidis mick@ics.forth.gr 2021-04-19T00:55:39+00:00 5640975003d0234da08559677e22ec25b9cb3267 This patch allows Linux to act as a crash kernel for use with kdump. Userspace will let the crash kernel know about the memory region it can use through linux,usable-memory property on the /memory node (overriding its reg property), and about the memory region where the elf core header of the previous kernel is saved, through a reserved-memory node with a compatible string of "linux,elfcorehdr". This approach is the least invasive and re-uses functionality already present. I tested this on riscv64 qemu and it works as expected, you may test it by retrieving the dmesg of the previous kernel through /proc/vmcore, using the vmcore-dmesg utility from kexec-tools. Signed-off-by: Nick Kossifidis <mick@ics.forth.gr> Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com> 
This patch allows Linux to act as a crash kernel for use with
kdump. Userspace will let the crash kernel know about the
memory region it can use through linux,usable-memory property
on the /memory node (overriding its reg property), and about the
memory region where the elf core header of the previous kernel
is saved, through a reserved-memory node with a compatible string
of "linux,elfcorehdr". This approach is the least invasive and
re-uses functionality already present.

I tested this on riscv64 qemu and it works as expected, you
may test it by retrieving the dmesg of the previous kernel
through /proc/vmcore, using the vmcore-dmesg utility from
kexec-tools.

Signed-off-by: Nick Kossifidis <mick@ics.forth.gr>
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
RISC-V: Add kdump support 2021-04-26T15:25:23+00:00 Nick Kossifidis mick@ics.forth.gr 2021-04-19T00:55:38+00:00 e53d28180d4d0fd12b6d2bde49cb87aa775b6ba8 This patch adds support for kdump, the kernel will reserve a region for the crash kernel and jump there on panic. In order for userspace tools (kexec-tools) to prepare the crash kernel kexec image, we also need to expose some information on /proc/iomem for the memory regions used by the kernel and for the region reserved for crash kernel. Note that on userspace the device tree is used to determine the system's memory layout so the "System RAM" on /proc/iomem is ignored. I tested this on riscv64 qemu and works as expected, you may test it by triggering a crash through /proc/sysrq_trigger: echo c > /proc/sysrq_trigger Signed-off-by: Nick Kossifidis <mick@ics.forth.gr> Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com> 
This patch adds support for kdump, the kernel will reserve a
region for the crash kernel and jump there on panic. In order
for userspace tools (kexec-tools) to prepare the crash kernel
kexec image, we also need to expose some information on
/proc/iomem for the memory regions used by the kernel and for
the region reserved for crash kernel. Note that on userspace
the device tree is used to determine the system's memory
layout so the "System RAM" on /proc/iomem is ignored.

I tested this on riscv64 qemu and works as expected, you may
test it by triggering a crash through /proc/sysrq_trigger:

echo c > /proc/sysrq_trigger

Signed-off-by: Nick Kossifidis <mick@ics.forth.gr>
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
RISC-V: Add kexec support 2021-04-26T15:25:21+00:00 Nick Kossifidis mick@ics.forth.gr 2021-04-19T00:55:36+00:00 fba8a8674f68a0628abae470dfcfbcb4a0d7a79e This patch adds support for kexec on RISC-V. On SMP systems it depends on HOTPLUG_CPU in order to be able to bring up all harts after kexec. It also needs a recent OpenSBI version that supports the HSM extension. I tested it on riscv64 QEMU on both an smp and a non-smp system. Signed-off-by: Nick Kossifidis <mick@ics.forth.gr> Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com> 
This patch adds support for kexec on RISC-V. On SMP systems it depends
on HOTPLUG_CPU in order to be able to bring up all harts after kexec.
It also needs a recent OpenSBI version that supports the HSM extension.
I tested it on riscv64 QEMU on both an smp and a non-smp system.

Signed-off-by: Nick Kossifidis <mick@ics.forth.gr>
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
riscv: syscall_table: Reduce W=1 compilation warnings noise 2021-03-10T04:46:04+00:00 Nanyong Sun sunnanyong@huawei.com 2021-03-05T11:33:29+00:00 a6a58ecf98c3f6d95123ee3e66ccb6f7672c6e68 Building riscv syscall table with W=1 throws the warning as following pattern: arch/riscv/kernel/syscall_table.c:14:36: warning: initialized field overwritten [-Woverride-init] 14 | #define __SYSCALL(nr, call) [nr] = (call), | ^ ./include/uapi/asm-generic/unistd.h:29:37: note: in expansion of macro ‘__SYSCALL’ 29 | #define __SC_COMP(_nr, _sys, _comp) __SYSCALL(_nr, _sys) | ^~~~~~~~~ ./include/uapi/asm-generic/unistd.h:34:1: note: in expansion of macro ‘__SC_COMP’ 34 | __SC_COMP(__NR_io_setup, sys_io_setup, compat_sys_io_setup) | ^~~~~~~~~ arch/riscv/kernel/syscall_table.c:14:36: note: (near initialization for ‘sys_call_table[0]’) 14 | #define __SYSCALL(nr, call) [nr] = (call), | ^ ./include/uapi/asm-generic/unistd.h:29:37: note: in expansion of macro ‘__SYSCALL’ 29 | #define __SC_COMP(_nr, _sys, _comp) __SYSCALL(_nr, _sys) | ^~~~~~~~~ ./include/uapi/asm-generic/unistd.h:34:1: note: in expansion of macro ‘__SC_COMP’ 34 | __SC_COMP(__NR_io_setup, sys_io_setup, compat_sys_io_setup) | ^~~~~~~~~ arch/riscv/kernel/syscall_table.c:14:36: warning: initialized field overwritten [-Woverride-init] ... Since we intentionally build the syscall tables this way,ignore the warning. Reported-by: Hulk Robot <hulkci@huawei.com> Signed-off-by: Nanyong Sun <sunnanyong@huawei.com> Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com> 
Building riscv syscall table with W=1 throws the warning as
following pattern:
arch/riscv/kernel/syscall_table.c:14:36: warning: initialized field overwritten [-Woverride-init]
   14 | #define __SYSCALL(nr, call) [nr] = (call),
      |                                    ^
./include/uapi/asm-generic/unistd.h:29:37: note: in expansion of macro ‘__SYSCALL’
   29 | #define __SC_COMP(_nr, _sys, _comp) __SYSCALL(_nr, _sys)
      |                                     ^~~~~~~~~
./include/uapi/asm-generic/unistd.h:34:1: note: in expansion of macro ‘__SC_COMP’
   34 | __SC_COMP(__NR_io_setup, sys_io_setup, compat_sys_io_setup)
      | ^~~~~~~~~
arch/riscv/kernel/syscall_table.c:14:36: note: (near initialization for ‘sys_call_table[0]’)
   14 | #define __SYSCALL(nr, call) [nr] = (call),
      |                                    ^
./include/uapi/asm-generic/unistd.h:29:37: note: in expansion of macro ‘__SYSCALL’
   29 | #define __SC_COMP(_nr, _sys, _comp) __SYSCALL(_nr, _sys)
      |                                     ^~~~~~~~~
./include/uapi/asm-generic/unistd.h:34:1: note: in expansion of macro ‘__SC_COMP’
   34 | __SC_COMP(__NR_io_setup, sys_io_setup, compat_sys_io_setup)
      | ^~~~~~~~~
arch/riscv/kernel/syscall_table.c:14:36: warning: initialized field overwritten [-Woverride-init]
...

Since we intentionally build the syscall tables this way,ignore the warning.

Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Nanyong Sun <sunnanyong@huawei.com>
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
riscv: Add kprobes supported 2021-01-14T23:09:06+00:00 Guo Ren guoren@linux.alibaba.com 2020-12-17T16:01:42+00:00 c22b0bcb1dd024cb9caad9230e3a387d8b061df5 This patch enables "kprobe & kretprobe" to work with ftrace interface. It utilized software breakpoint as single-step mechanism. Some instructions which can't be single-step executed must be simulated in kernel execution slot, such as: branch, jal, auipc, la ... Some instructions should be rejected for probing and we use a blacklist to filter, such as: ecall, ebreak, ... We use ebreak & c.ebreak to replace origin instruction and the kprobe handler prepares an executable memory slot for out-of-line execution with a copy of the original instruction being probed. In execution slot we add ebreak behind original instruction to simulate a single-setp mechanism. The patch is based on packi's work [1] and csky's work [2]. - The kprobes_trampoline.S is all from packi's patch - The single-step mechanism is new designed for riscv without hw single-step trap - The simulation codes are from csky - Frankly, all codes refer to other archs' implementation [1] https://lore.kernel.org/linux-riscv/20181113195804.22825-1-me@packi.ch/ [2] https://lore.kernel.org/linux-csky/20200403044150.20562-9-guoren@kernel.org/ Signed-off-by: Guo Ren <guoren@linux.alibaba.com> Co-developed-by: Patrick Stählin <me@packi.ch> Signed-off-by: Patrick Stählin <me@packi.ch> Acked-by: Masami Hiramatsu <mhiramat@kernel.org> Tested-by: Zong Li <zong.li@sifive.com> Reviewed-by: Pekka Enberg <penberg@kernel.org> Cc: Patrick Stählin <me@packi.ch> Cc: Palmer Dabbelt <palmerdabbelt@google.com> Cc: Björn Töpel <bjorn.topel@gmail.com> Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com> 
This patch enables "kprobe & kretprobe" to work with ftrace
interface. It utilized software breakpoint as single-step
mechanism.

Some instructions which can't be single-step executed must be
simulated in kernel execution slot, such as: branch, jal, auipc,
la ...

Some instructions should be rejected for probing and we use a
blacklist to filter, such as: ecall, ebreak, ...

We use ebreak & c.ebreak to replace origin instruction and the
kprobe handler prepares an executable memory slot for out-of-line
execution with a copy of the original instruction being probed.
In execution slot we add ebreak behind original instruction to
simulate a single-setp mechanism.

The patch is based on packi's work [1] and csky's work [2].
 - The kprobes_trampoline.S is all from packi's patch
 - The single-step mechanism is new designed for riscv without hw
   single-step trap
 - The simulation codes are from csky
 - Frankly, all codes refer to other archs' implementation

 [1] https://lore.kernel.org/linux-riscv/20181113195804.22825-1-me@packi.ch/
 [2] https://lore.kernel.org/linux-csky/20200403044150.20562-9-guoren@kernel.org/

Signed-off-by: Guo Ren <guoren@linux.alibaba.com>
Co-developed-by: Patrick Stählin <me@packi.ch>
Signed-off-by: Patrick Stählin <me@packi.ch>
Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
Tested-by: Zong Li <zong.li@sifive.com>
Reviewed-by: Pekka Enberg <penberg@kernel.org>
Cc: Patrick Stählin <me@packi.ch>
Cc: Palmer Dabbelt <palmerdabbelt@google.com>
Cc: Björn Töpel <bjorn.topel@gmail.com>
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
riscv: Fixup patch_text panic in ftrace 2021-01-14T23:09:04+00:00 Guo Ren guoren@linux.alibaba.com 2020-12-17T16:01:40+00:00 5ad84adf5456313e285734102367c861c436c5ed Just like arm64, we can't trace the function in the patch_text path. Here is the bug log: [ 45.234334] Unable to handle kernel paging request at virtual address ffffffd38ae80900 [ 45.242313] Oops [#1] [ 45.244600] Modules linked in: [ 45.247678] CPU: 0 PID: 11 Comm: migration/0 Not tainted 5.9.0-00025-g9b7db83-dirty #215 [ 45.255797] epc: ffffffe00021689a ra : ffffffe00021718e sp : ffffffe01afabb58 [ 45.262955] gp : ffffffe00136afa0 tp : ffffffe01af94d00 t0 : 0000000000000002 [ 45.270200] t1 : 0000000000000000 t2 : 0000000000000001 s0 : ffffffe01afabc08 [ 45.277443] s1 : ffffffe0013718a8 a0 : 0000000000000000 a1 : ffffffe01afabba8 [ 45.284686] a2 : 0000000000000000 a3 : 0000000000000000 a4 : c4c16ad38ae80900 [ 45.291929] a5 : 0000000000000000 a6 : 0000000000000000 a7 : 0000000052464e43 [ 45.299173] s2 : 0000000000000001 s3 : ffffffe000206a60 s4 : ffffffe000206a60 [ 45.306415] s5 : 00000000000009ec s6 : ffffffe0013718a8 s7 : c4c16ad38ae80900 [ 45.313658] s8 : 0000000000000004 s9 : 0000000000000001 s10: 0000000000000001 [ 45.320902] s11: 0000000000000003 t3 : 0000000000000001 t4 : ffffffffd192fe79 [ 45.328144] t5 : ffffffffb8f80000 t6 : 0000000000040000 [ 45.333472] status: 0000000200000100 badaddr: ffffffd38ae80900 cause: 000000000000000f [ 45.341514] ---[ end trace d95102172248fdcf ]--- [ 45.346176] note: migration/0[11] exited with preempt_count 1 (gdb) x /2i $pc => 0xffffffe00021689a <__do_proc_dointvec+196>: sd zero,0(s7) 0xffffffe00021689e <__do_proc_dointvec+200>: li s11,0 (gdb) bt 0 __do_proc_dointvec (tbl_data=0x0, table=0xffffffe01afabba8, write=0, buffer=0x0, lenp=0x7bf897061f9a0800, ppos=0x4, conv=0x0, data=0x52464e43) at kernel/sysctl.c:581 1 0xffffffe00021718e in do_proc_dointvec (data=<optimized out>, conv=<optimized out>, ppos=<optimized out>, lenp=<optimized out>, buffer=<optimized out>, write=<optimized out>, table=<optimized out>) at kernel/sysctl.c:964 2 proc_dointvec_minmax (ppos=<optimized out>, lenp=<optimized out>, buffer=<optimized out>, write=<optimized out>, table=<optimized out>) at kernel/sysctl.c:964 3 proc_do_static_key (table=<optimized out>, write=1, buffer=0x0, lenp=0x0, ppos=0x7bf897061f9a0800) at kernel/sysctl.c:1643 4 0xffffffe000206792 in ftrace_make_call (rec=<optimized out>, addr=<optimized out>) at arch/riscv/kernel/ftrace.c:109 5 0xffffffe0002c9c04 in __ftrace_replace_code (rec=0xffffffe01ae40c30, enable=3) at kernel/trace/ftrace.c:2503 6 0xffffffe0002ca0b2 in ftrace_replace_code (mod_flags=<optimized out>) at kernel/trace/ftrace.c:2530 7 0xffffffe0002ca26a in ftrace_modify_all_code (command=5) at kernel/trace/ftrace.c:2677 8 0xffffffe0002ca30e in __ftrace_modify_code (data=<optimized out>) at kernel/trace/ftrace.c:2703 9 0xffffffe0002c13b0 in multi_cpu_stop (data=0x0) at kernel/stop_machine.c:224 10 0xffffffe0002c0fde in cpu_stopper_thread (cpu=<optimized out>) at kernel/stop_machine.c:491 11 0xffffffe0002343de in smpboot_thread_fn (data=0x0) at kernel/smpboot.c:165 12 0xffffffe00022f8b4 in kthread (_create=0xffffffe01af0c040) at kernel/kthread.c:292 13 0xffffffe000201fac in handle_exception () at arch/riscv/kernel/entry.S:236 0xffffffe00020678a <+114>: auipc ra,0xffffe 0xffffffe00020678e <+118>: jalr -118(ra) # 0xffffffe000204714 <patch_text_nosync> 0xffffffe000206792 <+122>: snez a0,a0 (gdb) disassemble patch_text_nosync Dump of assembler code for function patch_text_nosync: 0xffffffe000204714 <+0>: addi sp,sp,-32 0xffffffe000204716 <+2>: sd s0,16(sp) 0xffffffe000204718 <+4>: sd ra,24(sp) 0xffffffe00020471a <+6>: addi s0,sp,32 0xffffffe00020471c <+8>: auipc ra,0x0 0xffffffe000204720 <+12>: jalr -384(ra) # 0xffffffe00020459c <patch_insn_write> 0xffffffe000204724 <+16>: beqz a0,0xffffffe00020472e <patch_text_nosync+26> 0xffffffe000204726 <+18>: ld ra,24(sp) 0xffffffe000204728 <+20>: ld s0,16(sp) 0xffffffe00020472a <+22>: addi sp,sp,32 0xffffffe00020472c <+24>: ret 0xffffffe00020472e <+26>: sd a0,-24(s0) 0xffffffe000204732 <+30>: auipc ra,0x4 0xffffffe000204736 <+34>: jalr -1464(ra) # 0xffffffe00020817a <flush_icache_all> 0xffffffe00020473a <+38>: ld a0,-24(s0) 0xffffffe00020473e <+42>: ld ra,24(sp) 0xffffffe000204740 <+44>: ld s0,16(sp) 0xffffffe000204742 <+46>: addi sp,sp,32 0xffffffe000204744 <+48>: ret (gdb) disassemble flush_icache_all-4 Dump of assembler code for function flush_icache_all: 0xffffffe00020817a <+0>: addi sp,sp,-8 0xffffffe00020817c <+2>: sd ra,0(sp) 0xffffffe00020817e <+4>: auipc ra,0xfffff 0xffffffe000208182 <+8>: jalr -1822(ra) # 0xffffffe000206a60 <ftrace_caller> 0xffffffe000208186 <+12>: ld ra,0(sp) 0xffffffe000208188 <+14>: addi sp,sp,8 0xffffffe00020818a <+0>: addi sp,sp,-16 0xffffffe00020818c <+2>: sd s0,0(sp) 0xffffffe00020818e <+4>: sd ra,8(sp) 0xffffffe000208190 <+6>: addi s0,sp,16 0xffffffe000208192 <+8>: li a0,0 0xffffffe000208194 <+10>: auipc ra,0xfffff 0xffffffe000208198 <+14>: jalr -410(ra) # 0xffffffe000206ffa <sbi_remote_fence_i> 0xffffffe00020819c <+18>: ld s0,0(sp) 0xffffffe00020819e <+20>: ld ra,8(sp) 0xffffffe0002081a0 <+22>: addi sp,sp,16 0xffffffe0002081a2 <+24>: ret (gdb) frame 5 (rec=0xffffffe01ae40c30, enable=3) at kernel/trace/ftrace.c:2503 2503 return ftrace_make_call(rec, ftrace_addr); (gdb) p /x rec->ip $2 = 0xffffffe00020817a -> flush_icache_all ! When we modified flush_icache_all's patchable-entry with ftrace_caller: - Insert ftrace_caller at flush_icache_all prologue. - Call flush_icache_all to sync I/Dcache, but flush_icache_all is just we modified by half. Link: https://lore.kernel.org/linux-riscv/CAJF2gTT=oDWesWe0JVWvTpGi60-gpbNhYLdFWN_5EbyeqoEDdw@mail.gmail.com/T/#t Signed-off-by: Guo Ren <guoren@linux.alibaba.com> Reviewed-by: Atish Patra <atish.patra@wdc.com> Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com> 
Just like arm64, we can't trace the function in the patch_text path.

Here is the bug log:

[   45.234334] Unable to handle kernel paging request at virtual address ffffffd38ae80900
[   45.242313] Oops [#1]
[   45.244600] Modules linked in:
[   45.247678] CPU: 0 PID: 11 Comm: migration/0 Not tainted 5.9.0-00025-g9b7db83-dirty #215
[   45.255797] epc: ffffffe00021689a ra : ffffffe00021718e sp : ffffffe01afabb58
[   45.262955]  gp : ffffffe00136afa0 tp : ffffffe01af94d00 t0 : 0000000000000002
[   45.270200]  t1 : 0000000000000000 t2 : 0000000000000001 s0 : ffffffe01afabc08
[   45.277443]  s1 : ffffffe0013718a8 a0 : 0000000000000000 a1 : ffffffe01afabba8
[   45.284686]  a2 : 0000000000000000 a3 : 0000000000000000 a4 : c4c16ad38ae80900
[   45.291929]  a5 : 0000000000000000 a6 : 0000000000000000 a7 : 0000000052464e43
[   45.299173]  s2 : 0000000000000001 s3 : ffffffe000206a60 s4 : ffffffe000206a60
[   45.306415]  s5 : 00000000000009ec s6 : ffffffe0013718a8 s7 : c4c16ad38ae80900
[   45.313658]  s8 : 0000000000000004 s9 : 0000000000000001 s10: 0000000000000001
[   45.320902]  s11: 0000000000000003 t3 : 0000000000000001 t4 : ffffffffd192fe79
[   45.328144]  t5 : ffffffffb8f80000 t6 : 0000000000040000
[   45.333472] status: 0000000200000100 badaddr: ffffffd38ae80900 cause: 000000000000000f
[   45.341514] ---[ end trace d95102172248fdcf ]---
[   45.346176] note: migration/0[11] exited with preempt_count 1

(gdb) x /2i $pc
=> 0xffffffe00021689a <__do_proc_dointvec+196>: sd      zero,0(s7)
   0xffffffe00021689e <__do_proc_dointvec+200>: li      s11,0

(gdb) bt
0  __do_proc_dointvec (tbl_data=0x0, table=0xffffffe01afabba8,
write=0, buffer=0x0, lenp=0x7bf897061f9a0800, ppos=0x4, conv=0x0,
data=0x52464e43) at kernel/sysctl.c:581
1  0xffffffe00021718e in do_proc_dointvec (data=<optimized out>,
conv=<optimized out>, ppos=<optimized out>, lenp=<optimized out>,
buffer=<optimized out>, write=<optimized out>, table=<optimized out>)
at kernel/sysctl.c:964
2  proc_dointvec_minmax (ppos=<optimized out>, lenp=<optimized out>,
buffer=<optimized out>, write=<optimized out>, table=<optimized out>)
at kernel/sysctl.c:964
3  proc_do_static_key (table=<optimized out>, write=1, buffer=0x0,
lenp=0x0, ppos=0x7bf897061f9a0800) at kernel/sysctl.c:1643
4  0xffffffe000206792 in ftrace_make_call (rec=<optimized out>,
addr=<optimized out>) at arch/riscv/kernel/ftrace.c:109
5  0xffffffe0002c9c04 in __ftrace_replace_code
(rec=0xffffffe01ae40c30, enable=3) at kernel/trace/ftrace.c:2503
6  0xffffffe0002ca0b2 in ftrace_replace_code (mod_flags=<optimized
out>) at kernel/trace/ftrace.c:2530
7  0xffffffe0002ca26a in ftrace_modify_all_code (command=5) at
kernel/trace/ftrace.c:2677
8  0xffffffe0002ca30e in __ftrace_modify_code (data=<optimized out>)
at kernel/trace/ftrace.c:2703
9  0xffffffe0002c13b0 in multi_cpu_stop (data=0x0) at kernel/stop_machine.c:224
10 0xffffffe0002c0fde in cpu_stopper_thread (cpu=<optimized out>) at
kernel/stop_machine.c:491
11 0xffffffe0002343de in smpboot_thread_fn (data=0x0) at kernel/smpboot.c:165
12 0xffffffe00022f8b4 in kthread (_create=0xffffffe01af0c040) at
kernel/kthread.c:292
13 0xffffffe000201fac in handle_exception () at arch/riscv/kernel/entry.S:236

   0xffffffe00020678a <+114>:   auipc   ra,0xffffe
   0xffffffe00020678e <+118>:   jalr    -118(ra) # 0xffffffe000204714 <patch_text_nosync>
   0xffffffe000206792 <+122>:   snez    a0,a0

(gdb) disassemble patch_text_nosync
Dump of assembler code for function patch_text_nosync:
   0xffffffe000204714 <+0>:     addi    sp,sp,-32
   0xffffffe000204716 <+2>:     sd      s0,16(sp)
   0xffffffe000204718 <+4>:     sd      ra,24(sp)
   0xffffffe00020471a <+6>:     addi    s0,sp,32
   0xffffffe00020471c <+8>:     auipc   ra,0x0
   0xffffffe000204720 <+12>:    jalr    -384(ra) # 0xffffffe00020459c <patch_insn_write>
   0xffffffe000204724 <+16>:    beqz    a0,0xffffffe00020472e <patch_text_nosync+26>
   0xffffffe000204726 <+18>:    ld      ra,24(sp)
   0xffffffe000204728 <+20>:    ld      s0,16(sp)
   0xffffffe00020472a <+22>:    addi    sp,sp,32
   0xffffffe00020472c <+24>:    ret
   0xffffffe00020472e <+26>:    sd      a0,-24(s0)
   0xffffffe000204732 <+30>:    auipc   ra,0x4
   0xffffffe000204736 <+34>:    jalr    -1464(ra) # 0xffffffe00020817a <flush_icache_all>
   0xffffffe00020473a <+38>:    ld      a0,-24(s0)
   0xffffffe00020473e <+42>:    ld      ra,24(sp)
   0xffffffe000204740 <+44>:    ld      s0,16(sp)
   0xffffffe000204742 <+46>:    addi    sp,sp,32
   0xffffffe000204744 <+48>:    ret

(gdb) disassemble flush_icache_all-4
Dump of assembler code for function flush_icache_all:
   0xffffffe00020817a <+0>:     addi    sp,sp,-8
   0xffffffe00020817c <+2>:     sd      ra,0(sp)
   0xffffffe00020817e <+4>:     auipc   ra,0xfffff
   0xffffffe000208182 <+8>:     jalr    -1822(ra) # 0xffffffe000206a60 <ftrace_caller>
   0xffffffe000208186 <+12>:    ld      ra,0(sp)
   0xffffffe000208188 <+14>:    addi    sp,sp,8
   0xffffffe00020818a <+0>:     addi    sp,sp,-16
   0xffffffe00020818c <+2>:     sd      s0,0(sp)
   0xffffffe00020818e <+4>:     sd      ra,8(sp)
   0xffffffe000208190 <+6>:     addi    s0,sp,16
   0xffffffe000208192 <+8>:     li      a0,0
   0xffffffe000208194 <+10>:    auipc   ra,0xfffff
   0xffffffe000208198 <+14>:    jalr    -410(ra) # 0xffffffe000206ffa <sbi_remote_fence_i>
   0xffffffe00020819c <+18>:    ld      s0,0(sp)
   0xffffffe00020819e <+20>:    ld      ra,8(sp)
   0xffffffe0002081a0 <+22>:    addi    sp,sp,16
   0xffffffe0002081a2 <+24>:    ret

(gdb) frame 5
(rec=0xffffffe01ae40c30, enable=3) at kernel/trace/ftrace.c:2503
2503                    return ftrace_make_call(rec, ftrace_addr);
(gdb) p /x rec->ip
$2 = 0xffffffe00020817a -> flush_icache_all !

When we modified flush_icache_all's patchable-entry with ftrace_caller:
 - Insert ftrace_caller at flush_icache_all prologue.
 - Call flush_icache_all to sync I/Dcache, but flush_icache_all is
just we modified by half.

Link: https://lore.kernel.org/linux-riscv/CAJF2gTT=oDWesWe0JVWvTpGi60-gpbNhYLdFWN_5EbyeqoEDdw@mail.gmail.com/T/#t
Signed-off-by: Guo Ren <guoren@linux.alibaba.com>
Reviewed-by: Atish Patra <atish.patra@wdc.com>
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
riscv: Fixup wrong ftrace remove cflag 2021-01-14T23:09:03+00:00 Guo Ren guoren@linux.alibaba.com 2020-12-17T16:01:39+00:00 67d945778099b14324811fe67c5aff2cda7a7ad5 We must use $(CC_FLAGS_FTRACE) instead of directly using -pg. It will cause -fpatchable-function-entry error. Signed-off-by: Guo Ren <guoren@linux.alibaba.com> Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com> 
We must use $(CC_FLAGS_FTRACE) instead of directly using -pg. It
will cause -fpatchable-function-entry error.

Signed-off-by: Guo Ren <guoren@linux.alibaba.com>
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
riscv: kernel: Drop unused clean rule 2020-12-11T01:42:34+00:00 Kefeng Wang wangkefeng.wang@huawei.com 2020-11-21T10:15:19+00:00 772e1b7c426762159e5150ecff5268e6e1f361d3 Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com> Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com> 
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>