linux.git/arch/riscv/include, branch v5.12

riscv: evaluate put_user() arg before enabling user access

2021-04-02T04:37:04+00:00

The  header has a problem with put_user(a, ptr) if
the 'a' is not a simple variable, such as a function. This can lead
to the compiler producing code as so:

1:	enable_user_access()
2:	evaluate 'a' into register 'r'
3:	put 'r' to 'ptr'
4:	disable_user_acess()

The issue is that 'a' is now being evaluated with the user memory
protections disabled. So we try and force the evaulation by assigning
'x' to __val at the start, and hoping the compiler barriers in
 enable_user_access() do the job of ordering step 2 before step 1.

This has shown up in a bug where 'a' sleeps and thus schedules out
and loses the SR_SUM flag. This isn't sufficient to fully fix, but
should reduce the window of opportunity. The first instance of this
we found is in scheudle_tail() where the code does:

$ less -N kernel/sched/core.c

4263  if (current->set_child_tid)
4264         put_user(task_pid_vnr(current), current->set_child_tid);

Here, the task_pid_vnr(current) is called within the block that has
enabled the user memory access. This can be made worse with KASAN
which makes task_pid_vnr() a rather large call with plenty of
opportunity to sleep.

Signed-off-by: Ben Dooks 
Reported-by: syzbot+e74b94fe601ab9552d69@syzkaller.appspotmail.com
Suggested-by: Arnd Bergman 

--
Changes since v1:
- fixed formatting and updated the patch description with more info

Changes since v2:
- fixed commenting on __put_user() (schwab@linux-m68k.org)

Change since v3:
- fixed RFC in patch title. Should be ready to merge.

Signed-off-by: Palmer Dabbelt

riscv: process: Fix no prototype for arch_dup_task_struct

2021-03-10T04:46:07+00:00

Fix the following W=1 compilation warning:
arch/riscv/kernel/process.c:114:5: warning: no previous prototype for ‘arch_dup_task_struct’ [-Wmissing-prototypes]
  114 | int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src)
      |     ^~~~~~~~~~~~~~~~~~~~

Reported-by: Hulk Robot 
Signed-off-by: Nanyong Sun 
Signed-off-by: Palmer Dabbelt

riscv: time: Fix no prototype for time_init

2021-03-10T04:46:03+00:00

Fix the following W=1 compilation warning:
arch/riscv/kernel/time.c:16:13: warning: no previous prototype for ‘time_init’ [-Wmissing-prototypes]
   16 | void __init time_init(void)
      |             ^~~~~~~~~

Reported-by: Hulk Robot 
Signed-off-by: Nanyong Sun 
Signed-off-by: Palmer Dabbelt

riscv: ptrace: Fix no prototype warnings

2021-03-10T04:46:02+00:00

Fix the following W=1 kernel compilation warnings:
arch/riscv/kernel/ftrace.c:186:6: warning: no previous prototype for ‘prepare_ftrace_return’ [-Wmissing-prototypes]
  186 | void prepare_ftrace_return(unsigned long *parent, unsigned long self_addr,
      |      ^~~~~~~~~~~~~~~~~~~~~
arch/riscv/kernel/ptrace.c:239:15: warning: no previous prototype for ‘do_syscall_trace_enter’ [-Wmissing-prototypes]
  239 | __visible int do_syscall_trace_enter(struct pt_regs *regs)
      |               ^~~~~~~~~~~~~~~~~~~~~~
arch/riscv/kernel/ptrace.c:262:16: warning: no previous prototype for ‘do_syscall_trace_exit’ [-Wmissing-prototypes]
  262 | __visible void do_syscall_trace_exit(struct pt_regs *regs)
      |                ^~~~~~~~~~~~~~~~~~~~~

Reported-by: Hulk Robot 
Signed-off-by: Nanyong Sun 
Signed-off-by: Palmer Dabbelt

riscv: irq: Fix no prototype warning

2021-03-10T04:46:00+00:00

Fix the following W=1 kernel compilation warning:
arch/riscv/kernel/irq.c:19:13: warning: no previous prototype for ‘init_IRQ’ [-Wmissing-prototypes]
   19 | void __init init_IRQ(void)
      |             ^~~~~~~~

Reported-by: Hulk Robot 
Signed-off-by: Nanyong Sun 
Signed-off-by: Palmer Dabbelt

riscv: traps: Fix no prototype warnings

2021-03-10T04:45:51+00:00

Fix all W=1 compilation warnings:'no previous prototype for' in arch/riscv/kernel/traps.c:
arch/riscv/kernel/traps.c:96:15: warning: no previous prototype for ‘do_trap_unknown’ [-Wmissing-prototypes]
   96 | DO_ERROR_INFO(do_trap_unknown,
      |               ^~~~~~~~~~~~~~~
arch/riscv/kernel/traps.c:91:27: note: in definition of macro ‘DO_ERROR_INFO’
   91 | asmlinkage __visible void name(struct pt_regs *regs)   \
      |                           ^~~~
arch/riscv/kernel/traps.c:98:15: warning: no previous prototype for ‘do_trap_insn_misaligned’ [-Wmissing-prototypes]
   98 | DO_ERROR_INFO(do_trap_insn_misaligned,
      |               ^~~~~~~~~~~~~~~~~~~~~~~
arch/riscv/kernel/traps.c:91:27: note: in definition of macro ‘DO_ERROR_INFO’
   91 | asmlinkage __visible void name(struct pt_regs *regs)   \
      |                           ^~~~
arch/riscv/kernel/traps.c:100:15: warning: no previous prototype for ‘do_trap_insn_fault’ [-Wmissing-prototypes]
...

Reported-by: Hulk Robot 
Signed-off-by: Nanyong Sun 
[Palmer: fix checkpatch warnings]
Signed-off-by: Palmer Dabbelt

RISC-V: correct enum sbi_ext_rfence_fid

2021-03-10T03:23:11+00:00

The constants in enum sbi_ext_rfence_fid should match the SBI
specification. See
https://github.com/riscv/riscv-sbi-doc/blob/master/riscv-sbi.adoc#78-function-listing

| Function Name               | FID | EID
| sbi_remote_fence_i          |   0 | 0x52464E43
| sbi_remote_sfence_vma       |   1 | 0x52464E43
| sbi_remote_sfence_vma_asid  |   2 | 0x52464E43
| sbi_remote_hfence_gvma_vmid |   3 | 0x52464E43
| sbi_remote_hfence_gvma      |   4 | 0x52464E43
| sbi_remote_hfence_vvma_asid |   5 | 0x52464E43
| sbi_remote_hfence_vvma      |   6 | 0x52464E43

Fixes: ecbacc2a3efd ("RISC-V: Add SBI v0.2 extension definitions")
Reported-by: Sean Anderson 
Signed-off-by: Heinrich Schuchardt 
Reviewed-by: Anup Patel 
Reviewed-by: Atish Patra 
Signed-off-by: Palmer Dabbelt

Merge tag 'riscv-for-linus-5.12-mw0' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux

2021-02-26T18:28:35+00:00

Pull RISC-V updates from Palmer Dabbelt:
"A handful of new RISC-V related patches for this merge window:

- A check to ensure drivers are properly using uaccess. This isn't
manifesting with any of the drivers I'm currently using, but may
catch errors in new drivers.

- Some preliminary support for the FU740, along with the HiFive
Unleashed it will appear on.

- NUMA support for RISC-V, which involves making the arm64 code
generic.

- Support for kasan on the vmalloc region.

- A handful of new drivers for the Kendryte K210, along with the DT
plumbing required to boot on a handful of K210-based boards.

- Support for allocating ASIDs.

- Preliminary support for kernels larger than 128MiB.

- Various other improvements to our KASAN support, including the
utilization of huge pages when allocating the KASAN regions.

We may have already found a bug with the KASAN_VMALLOC code, but it's
passing my tests. There's a fix in the works, but that will probably
miss the merge window.

* tag 'riscv-for-linus-5.12-mw0' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux: (75 commits)
riscv: Improve kasan population by using hugepages when possible
riscv: Improve kasan population function
riscv: Use KASAN_SHADOW_INIT define for kasan memory initialization
riscv: Improve kasan definitions
riscv: Get rid of MAX_EARLY_MAPPING_SIZE
soc: canaan: Sort the Makefile alphabetically
riscv: Disable KSAN_SANITIZE for vDSO
riscv: Remove unnecessary declaration
riscv: Add Canaan Kendryte K210 SD card defconfig
riscv: Update Canaan Kendryte K210 defconfig
riscv: Add Kendryte KD233 board device tree
riscv: Add SiPeed MAIXDUINO board device tree
riscv: Add SiPeed MAIX GO board device tree
riscv: Add SiPeed MAIX DOCK board device tree
riscv: Add SiPeed MAIX BiT board device tree
riscv: Update Canaan Kendryte K210 device tree
dt-bindings: add resets property to dw-apb-timer
dt-bindings: fix sifive gpio properties
dt-bindings: update sifive uart compatible string
dt-bindings: update sifive clint compatible string
...

riscv: Improve kasan definitions

2021-02-23T02:44:53+00:00

There is no functional change here, only improvement in code readability
by adding comments to explain where the kasan constants come from and by
replacing hardcoded numerical constant by the corresponding define.

Note that the comments come from arm64.

Signed-off-by: Alexandre Ghiti 
Signed-off-by: Palmer Dabbelt

riscv: Remove unnecessary declaration

2021-02-23T01:51:22+00:00

max_low_pfn and min_low_pfn are declared in linux/memblock.h,
and it also is included in arch/riscv/mm/init.c, drop unnecessary
declaration.

Signed-off-by: Kefeng Wang 
Reviewed-by: Atish Patra 
Signed-off-by: Palmer Dabbelt