linux-kernel - Re: [PATCH] RISC-V: Remove unused code from STRICT_KERNEL

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Date:   Tue, 05 May 2020 17:03:18 -0700 (PDT)
From:   Palmer Dabbelt <palmer@...belt.com>
To:     atishp@...shpatra.org
CC:     Atish Patra <Atish.Patra@....com>, aou@...s.berkeley.edu,
        Anup Patel <Anup.Patel@....com>, linux-kernel@...r.kernel.org,
        zong.li@...ive.com, Paul Walmsley <paul.walmsley@...ive.com>,
        linux-riscv@...ts.infradead.org
Subject:     Re: [PATCH] RISC-V: Remove unused code from STRICT_KERNEL_RWX

On Tue, 05 May 2020 17:00:05 PDT (-0700), atishp@...shpatra.org wrote:
> On Tue, May 5, 2020 at 4:55 PM Palmer Dabbelt <palmer@...belt.com> wrote:
>>
>> On Sun, 03 May 2020 21:03:19 PDT (-0700), Atish Patra wrote:
>> > This patch removes the unused functions set_kernel_text_rw/ro.
>> > Currently, it is not being invoked from anywhere and no other architecture
>> > (except arm) uses this code. Even in ARM, these functions are not invoked
>> > from anywhere currently.
>> >
>> > Fixes: d27c3c90817e ("riscv: add STRICT_KERNEL_RWX support")
>> >
>> > Signed-off-by: Atish Patra <atish.patra@....com>
>> > ---
>> >  arch/riscv/mm/init.c | 16 ----------------
>> >  1 file changed, 16 deletions(-)
>> >
>> > diff --git a/arch/riscv/mm/init.c b/arch/riscv/mm/init.c
>> > index b55be44ff9bd..ba60a581e9b6 100644
>> > --- a/arch/riscv/mm/init.c
>> > +++ b/arch/riscv/mm/init.c
>> > @@ -501,22 +501,6 @@ static inline void setup_vm_final(void)
>> >  #endif /* CONFIG_MMU */
>> >
>> >  #ifdef CONFIG_STRICT_KERNEL_RWX
>> > -void set_kernel_text_rw(void)
>> > -{
>> > -     unsigned long text_start = (unsigned long)_text;
>> > -     unsigned long text_end = (unsigned long)_etext;
>> > -
>> > -     set_memory_rw(text_start, (text_end - text_start) >> PAGE_SHIFT);
>> > -}
>> > -
>> > -void set_kernel_text_ro(void)
>> > -{
>> > -     unsigned long text_start = (unsigned long)_text;
>> > -     unsigned long text_end = (unsigned long)_etext;
>> > -
>> > -     set_memory_ro(text_start, (text_end - text_start) >> PAGE_SHIFT);
>> > -}
>> > -
>> >  void mark_rodata_ro(void)
>> >  {
>> >       unsigned long text_start = (unsigned long)_text;
>>
>> Thanks, this is on fixes.  Are you going to remove the ARM code as well?
>>
>
> Yeah and also I realized that I forgot to remove the declarations from
> the header file.
> My bad. I will send out a v2. Please drop this one and take v2.

I just fixed it up

commit 73cb8e2a5863ccc5215660f5123db621bd57dff7
gpg: Signature made Tue 05 May 2020 05:02:17 PM PDT
gpg:                using RSA key 2B3C3747446843B24A943A7A2E1319F35FBB1889
gpg:                issuer "palmer@...belt.com"
gpg: Good signature from "Palmer Dabbelt <palmer@...belt.com>" [ultimate]
gpg:                 aka "Palmer Dabbelt <palmerdabbelt@...gle.com>" [ultimate]
Author: Atish Patra <atish.patra@....com>
Date:   Sun May 3 21:03:19 2020 -0700

    RISC-V: Remove unused code from STRICT_KERNEL_RWX
    
    This patch removes the unused functions set_kernel_text_rw/ro.
    Currently, it is not being invoked from anywhere and no other architecture
    (except arm) uses this code. Even in ARM, these functions are not invoked
    from anywhere currently.
    
    Fixes: d27c3c90817e ("riscv: add STRICT_KERNEL_RWX support")
    Signed-off-by: Atish Patra <atish.patra@....com>
    Reviewed-by: Zong Li <zong.li@...ive.com>
    Signed-off-by: Palmer Dabbelt <palmerdabbelt@...gle.com>

diff --git a/arch/riscv/include/asm/set_memory.h b/arch/riscv/include/asm/set_memory.h
index c38df4771c09..4c5bae7ca01c 100644
--- a/arch/riscv/include/asm/set_memory.h
+++ b/arch/riscv/include/asm/set_memory.h
@@ -22,14 +22,6 @@ static inline int set_memory_x(unsigned long addr, int numpages) { return 0; }
 static inline int set_memory_nx(unsigned long addr, int numpages) { return 0; }
 #endif
 
-#ifdef CONFIG_STRICT_KERNEL_RWX
-void set_kernel_text_ro(void);
-void set_kernel_text_rw(void);
-#else
-static inline void set_kernel_text_ro(void) { }
-static inline void set_kernel_text_rw(void) { }
-#endif
-
 int set_direct_map_invalid_noflush(struct page *page);
 int set_direct_map_default_noflush(struct page *page);
 
diff --git a/arch/riscv/mm/init.c b/arch/riscv/mm/init.c
index 5b813532db59..27a334106708 100644
--- a/arch/riscv/mm/init.c
+++ b/arch/riscv/mm/init.c
@@ -502,22 +502,6 @@ static inline void setup_vm_final(void)
 #endif /* CONFIG_MMU */
 
 #ifdef CONFIG_STRICT_KERNEL_RWX
-void set_kernel_text_rw(void)
-{
-	unsigned long text_start = (unsigned long)_text;
-	unsigned long text_end = (unsigned long)_etext;
-
-	set_memory_rw(text_start, (text_end - text_start) >> PAGE_SHIFT);
-}
-
-void set_kernel_text_ro(void)
-{
-	unsigned long text_start = (unsigned long)_text;
-	unsigned long text_end = (unsigned long)_etext;
-
-	set_memory_ro(text_start, (text_end - text_start) >> PAGE_SHIFT);
-}
-
 void mark_rodata_ro(void)
 {
 	unsigned long text_start = (unsigned long)_text;