Re: [PATCH 5.10.y] powerpc/rtas: Prevent Spectre v1 gadget construction in sys_rtas()

[Sasha Levin <sashal@kernel.org>]

[ Sasha's backport helper bot ]

Hi,

✅ All tests passed successfully. No issues detected.
No action required from the submitter.

The upstream commit SHA1 provided is correct: 0974d03eb479384466d828d65637814bee6b26d7

WARNING: Author mismatch between patch and upstream commit:
Backport author: Cliff Liu<donghua.liu@windriver.com>
Commit author: Nathan Lynch<nathanl@linux.ibm.com>

Status in newer kernel trees:
6.14.y | Present (exact SHA1)
6.13.y | Present (exact SHA1)
6.12.y | Present (exact SHA1)
6.6.y | Not found
6.1.y | Not found
5.15.y | Not found

Note: The patch differs from the upstream commit:
---
1:  0974d03eb4793 ! 1:  4d5f35b16ee3f powerpc/rtas: Prevent Spectre v1 gadget construction in sys_rtas()
    @@ Metadata
      ## Commit message ##
         powerpc/rtas: Prevent Spectre v1 gadget construction in sys_rtas()
     
    +    [ Upstream commit 0974d03eb479384466d828d65637814bee6b26d7 ]
    +
         Smatch warns:
     
           arch/powerpc/kernel/rtas.c:1932 __do_sys_rtas() warn: potential
    @@ Commit message
         Reviewed-by: Breno Leitao <leitao@debian.org>
         Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
         Link: https://msgid.link/20240530-sys_rtas-nargs-nret-v1-1-129acddd4d89@linux.ibm.com
    +    Signed-off-by: Cliff Liu <donghua.liu@windriver.com>
    +    Signed-off-by: He Zhe <Zhe.He@windriver.com>
     
      ## arch/powerpc/kernel/rtas.c ##
     @@
    - #include <linux/lockdep.h>
    - #include <linux/memblock.h>
    - #include <linux/mutex.h>
    + #include <linux/capability.h>
    + #include <linux/delay.h>
    + #include <linux/cpu.h>
     +#include <linux/nospec.h>
    - #include <linux/of.h>
    - #include <linux/of_fdt.h>
    - #include <linux/reboot.h>
    + #include <linux/sched.h>
    + #include <linux/smp.h>
    + #include <linux/completion.h>
     @@ arch/powerpc/kernel/rtas.c: SYSCALL_DEFINE1(rtas, struct rtas_args __user *, uargs)
      	    || nargs + nret > ARRAY_SIZE(args.args))
      		return -EINVAL;
---

Results of testing on various branches:

| Branch                    | Patch Apply | Build Test |
|---------------------------|-------------|------------|
| stable/linux-5.10.y       |  Success    |  Success   |