Re: [PATCH 6.1.y v2 3/4] mm: refactor arch_calc_vm_flag_bits() and arm64 MTE handling

[Harshit Mogalapalli <harshit.m.mogalapalli@xxxxxxxxxx>]

Hi Sasha,

On 19/11/24 10:06, Sasha Levin wrote:
> [ Sasha's backport helper bot ]
>
> Hi,
>
> The upstream commit SHA1 provided is correct: 5baf8b037debf4ec60108ccfeccb8636d1dbad81

Nice bot!

Just few thoughts:

> Commit in newer trees:
>
> |-----------------|----------------------------------------------|
> | 6.11.y          |  Present (different SHA1: 9f5efc1137ba)      |
> | 6.6.y           |  Not found                                   |
> | 6.1.y           |  Not found                                   |
> |-----------------|----------------------------------------------|


Given that this patch is for 6.1.y, it(6.1.y) need not be considered as 
newer tree I think ?

Also the backport for 6.6.y is present on lore.stable [1], so the 
backport not being present in stable-6.6.y might be not very useful, as 
it is possible for people to send the backport to multiple trees in the 
same stable update cycle(before 6.6.y has the backport included) -- 
instead could we run this while queuing up(maybe warn if it is neither 
present in stable-queue-6.6 nor in stable-6.6.y ?) ?


[1] 
https://lore.kernel.org/all/7c0218d03fd2119025d8cbc1b814639cf09314e0.1731672733.git.lorenzo.stoakes@xxxxxxxxxx/

Thanks,
Harshit

> Note: The patch differs from the upstream commit:
> ---
> --- -	2024-11-18 17:15:02.588328592 -0500
> +++ /tmp/tmp.LhvhUpwE7J	2024-11-18 17:15:02.577003940 -0500
> @@ -50,29 +50,29 @@
>   Cc: Will Deacon <will@xxxxxxxxxx>
>   Cc: <stable@xxxxxxxxxxxxxxx>
>   Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
> +Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@xxxxxxxxxx>
>   ---
> - arch/arm64/include/asm/mman.h  | 10 +++++++---
> - arch/parisc/include/asm/mman.h |  5 +++--
> - include/linux/mman.h           |  7 ++++---
> - mm/mmap.c                      |  2 +-
> - mm/nommu.c                     |  2 +-
> - mm/shmem.c                     |  3 ---
> - 6 files changed, 16 insertions(+), 13 deletions(-)
> + arch/arm64/include/asm/mman.h | 10 +++++++---
> + include/linux/mman.h          |  7 ++++---
> + mm/mmap.c                     |  2 +-
> + mm/nommu.c                    |  2 +-
> + mm/shmem.c                    |  3 ---
> + 5 files changed, 13 insertions(+), 11 deletions(-)
>   
>   diff --git a/arch/arm64/include/asm/mman.h b/arch/arm64/include/asm/mman.h
> -index 9e39217b4afbb..798d965760d43 100644
> +index 5966ee4a6154..ef35c52aabd6 100644
>   --- a/arch/arm64/include/asm/mman.h
>   +++ b/arch/arm64/include/asm/mman.h
> -@@ -6,6 +6,8 @@
> +@@ -3,6 +3,8 @@
> + #define __ASM_MMAN_H__
>    
> - #ifndef BUILD_VDSO
>    #include <linux/compiler.h>
>   +#include <linux/fs.h>
>   +#include <linux/shmem_fs.h>
>    #include <linux/types.h>
> + #include <uapi/asm/mman.h>
>    
> - static inline unsigned long arch_calc_vm_prot_bits(unsigned long prot,
> -@@ -31,19 +33,21 @@ static inline unsigned long arch_calc_vm_prot_bits(unsigned long prot,
> +@@ -21,19 +23,21 @@ static inline unsigned long arch_calc_vm_prot_bits(unsigned long prot,
>    }
>    #define arch_calc_vm_prot_bits(prot, pkey) arch_calc_vm_prot_bits(prot, pkey)
>    
> @@ -97,37 +97,8 @@
>    
>    static inline bool arch_validate_prot(unsigned long prot,
>    	unsigned long addr __always_unused)
> -diff --git a/arch/parisc/include/asm/mman.h b/arch/parisc/include/asm/mman.h
> -index 89b6beeda0b86..663f587dc7896 100644
> ---- a/arch/parisc/include/asm/mman.h
> -+++ b/arch/parisc/include/asm/mman.h
> -@@ -2,6 +2,7 @@
> - #ifndef __ASM_MMAN_H__
> - #define __ASM_MMAN_H__
> -
> -+#include <linux/fs.h>
> - #include <uapi/asm/mman.h>
> -
> - /* PARISC cannot allow mdwe as it needs writable stacks */
> -@@ -11,7 +12,7 @@ static inline bool arch_memory_deny_write_exec_supported(void)
> - }
> - #define arch_memory_deny_write_exec_supported arch_memory_deny_write_exec_supported
> -
> --static inline unsigned long arch_calc_vm_flag_bits(unsigned long flags)
> -+static inline unsigned long arch_calc_vm_flag_bits(struct file *file, unsigned long flags)
> - {
> - 	/*
> - 	 * The stack on parisc grows upwards, so if userspace requests memory
> -@@ -23,6 +24,6 @@ static inline unsigned long arch_calc_vm_flag_bits(unsigned long flags)
> -
> - 	return 0;
> - }
> --#define arch_calc_vm_flag_bits(flags) arch_calc_vm_flag_bits(flags)
> -+#define arch_calc_vm_flag_bits(file, flags) arch_calc_vm_flag_bits(file, flags)
> -
> - #endif /* __ASM_MMAN_H__ */
>   diff --git a/include/linux/mman.h b/include/linux/mman.h
> -index 8ddca62d6460b..a842783ffa62b 100644
> +index 58b3abd457a3..21ea08b919d9 100644
>   --- a/include/linux/mman.h
>   +++ b/include/linux/mman.h
>   @@ -2,6 +2,7 @@
> @@ -138,7 +109,7 @@
>    #include <linux/mm.h>
>    #include <linux/percpu_counter.h>
>    
> -@@ -94,7 +95,7 @@ static inline void vm_unacct_memory(long pages)
> +@@ -90,7 +91,7 @@ static inline void vm_unacct_memory(long pages)
>    #endif
>    
>    #ifndef arch_calc_vm_flag_bits
> @@ -147,7 +118,7 @@
>    #endif
>    
>    #ifndef arch_validate_prot
> -@@ -151,13 +152,13 @@ calc_vm_prot_bits(unsigned long prot, unsigned long pkey)
> +@@ -147,12 +148,12 @@ calc_vm_prot_bits(unsigned long prot, unsigned long pkey)
>     * Combine the mmap "flags" argument into "vm_flags" used internally.
>     */
>    static inline unsigned long
> @@ -157,49 +128,51 @@
>    	return _calc_vm_trans(flags, MAP_GROWSDOWN,  VM_GROWSDOWN ) |
>    	       _calc_vm_trans(flags, MAP_LOCKED,     VM_LOCKED    ) |
>    	       _calc_vm_trans(flags, MAP_SYNC,	     VM_SYNC      ) |
> - 	       _calc_vm_trans(flags, MAP_STACK,	     VM_NOHUGEPAGE) |
>   -	       arch_calc_vm_flag_bits(flags);
>   +	       arch_calc_vm_flag_bits(file, flags);
>    }
>    
>    unsigned long vm_commit_limit(void);
>   diff --git a/mm/mmap.c b/mm/mmap.c
> -index ab71d4c3464cd..aee5fa08ae5d1 100644
> +index 4bfec4df51c2..322677f61d30 100644
>   --- a/mm/mmap.c
>   +++ b/mm/mmap.c
> -@@ -344,7 +344,7 @@ unsigned long do_mmap(struct file *file, unsigned long addr,
> +@@ -1316,7 +1316,7 @@ unsigned long do_mmap(struct file *file, unsigned long addr,
>    	 * to. we assume access permissions have been handled by the open
>    	 * of the memory object, so we don't do any here.
>    	 */
> --	vm_flags |= calc_vm_prot_bits(prot, pkey) | calc_vm_flag_bits(flags) |
> -+	vm_flags |= calc_vm_prot_bits(prot, pkey) | calc_vm_flag_bits(file, flags) |
> +-	vm_flags = calc_vm_prot_bits(prot, pkey) | calc_vm_flag_bits(flags) |
> ++	vm_flags = calc_vm_prot_bits(prot, pkey) | calc_vm_flag_bits(file, flags) |
>    			mm->def_flags | VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC;
>    
> - 	/* Obtain the address to map to. we verify (or select) it and ensure
> + 	if (flags & MAP_LOCKED)
>   diff --git a/mm/nommu.c b/mm/nommu.c
> -index 635d028d647b3..e9b5f527ab5b4 100644
> +index e0428fa57526..859ba6bdeb9c 100644
>   --- a/mm/nommu.c
>   +++ b/mm/nommu.c
> -@@ -842,7 +842,7 @@ static unsigned long determine_vm_flags(struct file *file,
> +@@ -903,7 +903,7 @@ static unsigned long determine_vm_flags(struct file *file,
>    {
>    	unsigned long vm_flags;
>    
>   -	vm_flags = calc_vm_prot_bits(prot, 0) | calc_vm_flag_bits(flags);
>   +	vm_flags = calc_vm_prot_bits(prot, 0) | calc_vm_flag_bits(file, flags);
> + 	/* vm_flags |= mm->def_flags; */
>    
> - 	if (!file) {
> - 		/*
> + 	if (!(capabilities & NOMMU_MAP_DIRECT)) {
>   diff --git a/mm/shmem.c b/mm/shmem.c
> -index 4ba1d00fabdaa..e87f5d6799a7b 100644
> +index 0e1fbc53717d..d1a33f66cc7f 100644
>   --- a/mm/shmem.c
>   +++ b/mm/shmem.c
> -@@ -2733,9 +2733,6 @@ static int shmem_mmap(struct file *file, struct vm_area_struct *vma)
> +@@ -2308,9 +2308,6 @@ static int shmem_mmap(struct file *file, struct vm_area_struct *vma)
>    	if (ret)
>    		return ret;
>    
>   -	/* arm64 - allow memory tagging on RAM-based files */
> --	vm_flags_set(vma, VM_MTE_ALLOWED);
> +-	vma->vm_flags |= VM_MTE_ALLOWED;
>   -
>    	file_accessed(file);
> - 	/* This is anonymous shared memory if it is unlinked at the time of mmap */
> - 	if (inode->i_nlink)
> + 	vma->vm_ops = &shmem_vm_ops;
> + 	return 0;
> +--
> +2.47.0
> +
> ---
>
> Results of testing on various branches:
>
> | Branch                    | Patch Apply | Build Test |
> |---------------------------|-------------|------------|
> | stable/linux-6.1.y        |  Success    |  Success   |