ARM: 9359/1: flush: check if the folio is reserved for no-mapping addresses

jira LE-1907
cve CVE-2024-26947
Rebuild_History Non-Buildable kernel-5.14.0-427.37.1.el9_4
commit-author Yongqiang Liu <liuyongqiang13@huawei.com>
commit 0c66c6f
Empty-Commit: Cherry-Pick Conflicts during history rebuild.
Will be included in final tarball splat. Ref for failed cherry-pick at:
ciq/ciq_backports/kernel-5.14.0-427.37.1.el9_4/0c66c6f4.failed

Since commit a4d5613 ("arm: extend pfn_valid to take into account
freed memory map alignment") changes the semantics of pfn_valid() to check
presence of the memory map for a PFN. A valid page for an address which
is reserved but not mapped by the kernel[1], the system crashed during
some uio test with the following memory layout:

 node   0: [mem 0x00000000c0a00000-0x00000000cc8fffff]
 node   0: [mem 0x00000000d0000000-0x00000000da1fffff]
 the uio layout is：0xc0900000, 0x100000

the crash backtrace like:

  Unable to handle kernel paging request at virtual address bff00000
  [...]
  CPU: 1 PID: 465 Comm: startapp.bin Tainted: G           O      5.10.0 #1
  Hardware name: Generic DT based system
  PC is at b15_flush_kern_dcache_area+0x24/0x3c
  LR is at __sync_icache_dcache+0x6c/0x98
  [...]
   (b15_flush_kern_dcache_area) from (__sync_icache_dcache+0x6c/0x98)
   (__sync_icache_dcache) from (set_pte_at+0x28/0x54)
   (set_pte_at) from (remap_pfn_range+0x1a0/0x274)
   (remap_pfn_range) from (uio_mmap+0x184/0x1b8 [uio])
   (uio_mmap [uio]) from (__mmap_region+0x264/0x5f4)
   (__mmap_region) from (__do_mmap_mm+0x3ec/0x440)
   (__do_mmap_mm) from (do_mmap+0x50/0x58)
   (do_mmap) from (vm_mmap_pgoff+0xfc/0x188)
   (vm_mmap_pgoff) from (ksys_mmap_pgoff+0xac/0xc4)
   (ksys_mmap_pgoff) from (ret_fast_syscall+0x0/0x5c)
  Code: e0801001 e2423001 e1c00003 f57ff04f (ee070f3e)
  ---[ end trace 09cf0734c3805d52 ]---
  Kernel panic - not syncing: Fatal exception

So check if PG_reserved was set to solve this issue.

[1]: https://lore.kernel.org/lkml/Zbtdue57RO0QScJM@linux.ibm.com/

Fixes: a4d5613 ("arm: extend pfn_valid to take into account freed memory map alignment")
	Suggested-by: Mike Rapoport <rppt@linux.ibm.com>
	Signed-off-by: Yongqiang Liu <liuyongqiang13@huawei.com>
	Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
(cherry picked from commit 0c66c6f)
	Signed-off-by: Jonathan Maple <jmaple@ciq.com>

# Conflicts:
#	arch/arm/mm/flush.c

Author: PlaidCat

ciq/ciq_backports/kernel-5.14.0-427.37.1.el9_4/0c66c6f4.failed

@@ -0,0 +1,80 @@
+ARM: 9359/1: flush: check if the folio is reserved for no-mapping addresses
+
+jira LE-1907
+cve CVE-2024-26947
+Rebuild_History Non-Buildable kernel-5.14.0-427.37.1.el9_4
+commit-author Yongqiang Liu <liuyongqiang13@huawei.com>
+commit 0c66c6f4e21cb22220cbd8821c5c73fc157d20dc
+Empty-Commit: Cherry-Pick Conflicts during history rebuild.
+Will be included in final tarball splat. Ref for failed cherry-pick at:
+ciq/ciq_backports/kernel-5.14.0-427.37.1.el9_4/0c66c6f4.failed
+
+Since commit a4d5613c4dc6 ("arm: extend pfn_valid to take into account
+freed memory map alignment") changes the semantics of pfn_valid() to check
+presence of the memory map for a PFN. A valid page for an address which
+is reserved but not mapped by the kernel[1], the system crashed during
+some uio test with the following memory layout:
+
+ node   0: [mem 0x00000000c0a00000-0x00000000cc8fffff]
+ node   0: [mem 0x00000000d0000000-0x00000000da1fffff]
+ the uio layout is：0xc0900000, 0x100000
+
+the crash backtrace like:
+
+  Unable to handle kernel paging request at virtual address bff00000
+  [...]
+  CPU: 1 PID: 465 Comm: startapp.bin Tainted: G           O      5.10.0 #1
+  Hardware name: Generic DT based system
+  PC is at b15_flush_kern_dcache_area+0x24/0x3c
+  LR is at __sync_icache_dcache+0x6c/0x98
+  [...]
+   (b15_flush_kern_dcache_area) from (__sync_icache_dcache+0x6c/0x98)
+   (__sync_icache_dcache) from (set_pte_at+0x28/0x54)
+   (set_pte_at) from (remap_pfn_range+0x1a0/0x274)
+   (remap_pfn_range) from (uio_mmap+0x184/0x1b8 [uio])
+   (uio_mmap [uio]) from (__mmap_region+0x264/0x5f4)
+   (__mmap_region) from (__do_mmap_mm+0x3ec/0x440)
+   (__do_mmap_mm) from (do_mmap+0x50/0x58)
+   (do_mmap) from (vm_mmap_pgoff+0xfc/0x188)
+   (vm_mmap_pgoff) from (ksys_mmap_pgoff+0xac/0xc4)
+   (ksys_mmap_pgoff) from (ret_fast_syscall+0x0/0x5c)
+  Code: e0801001 e2423001 e1c00003 f57ff04f (ee070f3e)
+  ---[ end trace 09cf0734c3805d52 ]---
+  Kernel panic - not syncing: Fatal exception
+
+So check if PG_reserved was set to solve this issue.
+
+[1]: https://lore.kernel.org/lkml/Zbtdue57RO0QScJM@linux.ibm.com/
+
+Fixes: a4d5613c4dc6 ("arm: extend pfn_valid to take into account freed memory map alignment")
+	Suggested-by: Mike Rapoport <rppt@linux.ibm.com>
+	Signed-off-by: Yongqiang Liu <liuyongqiang13@huawei.com>
+	Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
+(cherry picked from commit 0c66c6f4e21cb22220cbd8821c5c73fc157d20dc)
+	Signed-off-by: Jonathan Maple <jmaple@ciq.com>
+
+# Conflicts:
+#	arch/arm/mm/flush.c
+diff --cc arch/arm/mm/flush.c
+index 7ff9feea13a6,0749cf8a6637..000000000000
+--- a/arch/arm/mm/flush.c
++++ b/arch/arm/mm/flush.c
+@@@ -279,9 -295,12 +279,16 @@@ void __sync_icache_dcache(pte_t pteval
+  	if (!pfn_valid(pfn))
+  		return;
+  
+++<<<<<<< HEAD
+ +	page = pfn_to_page(pfn);
+++=======
++ 	folio = page_folio(pfn_to_page(pfn));
++ 	if (folio_test_reserved(folio))
++ 		return;
++ 
+++>>>>>>> 0c66c6f4e21c (ARM: 9359/1: flush: check if the folio is reserved for no-mapping addresses)
+  	if (cache_is_vipt_aliasing())
+ -		mapping = folio_flush_mapping(folio);
+ +		mapping = page_mapping_file(page);
+  	else
+  		mapping = NULL;
+  
+* Unmerged path arch/arm/mm/flush.c