| 1 | Handle better cases where there might be non-page-aligned RAM e820 | 1 | The current implementation of e820__register_nosave_regions suffers from |
|---|---|---|---|
| 2 | regions so we don't end up marking kernel memory as nosave. | 2 | multiple serious issues: |
| 3 | - The end of last region is tracked by PFN, causing it to find holes | ||
| 4 | that aren't there if two consecutive subpage regions are present | ||
| 5 | - The nosave PFN ranges derived from holes are rounded out (instead of | ||
| 6 | rounded in) which makes it inconsistent with how explicitly reserved | ||
| 7 | regions are handled | ||
| 3 | 8 | ||
| 4 | This also simplifies the calculation of nosave ranges by treating | 9 | Fix this by: |
| 5 | non-RAM regions as holes. | 10 | - Treating reserved regions as if they were holes, to ensure consistent |
| 11 | handling (rounding out nosave PFN ranges is more correct as the | ||
| 12 | kernel does not use partial pages) | ||
| 13 | - Tracking the end of the last RAM region by address instead of pages | ||
| 14 | to detect holes more precisely | ||
| 6 | 15 | ||
| 16 | Cc: stable@vger.kernel.org | ||
| 7 | Fixes: e5540f875404 ("x86/boot/e820: Consolidate 'struct e820_entry *entry' local variable names") | 17 | Fixes: e5540f875404 ("x86/boot/e820: Consolidate 'struct e820_entry *entry' local variable names") |
| 8 | Tested-by: Roberto Ricci <io@r-ricci.it> | ||
| 9 | Reported-by: Roberto Ricci <io@r-ricci.it> | 18 | Reported-by: Roberto Ricci <io@r-ricci.it> |
| 10 | Closes: https://lore.kernel.org/all/Z4WFjBVHpndct7br@desktop0a/ | 19 | Closes: https://lore.kernel.org/all/Z4WFjBVHpndct7br@desktop0a/ |
| 11 | Signed-off-by: msizanoen <msizanoen@qtmlabs.xyz> | 20 | Signed-off-by: Myrrh Periwinkle <myrrhperiwinkle@qtmlabs.xyz> |
| 12 | Cc: stable@vger.kernel.org | ||
| 13 | --- | 21 | --- |
| 14 | The issue of the kernel failing to resume from hibernation after | 22 | The issue of the kernel failing to resume from hibernation after |
| 15 | kexec_load() is used is likely due to kexec-tools passing in a different | 23 | kexec_load() is used is likely due to kexec-tools passing in a different |
| 16 | e820 memory map from the one provided by system firmware, causing the | 24 | e820 memory map from the one provided by system firmware, causing the |
| 17 | e820 consistency check to fail. That issue is not addressed in this | 25 | e820 consistency check to fail. That issue is not addressed in this |
| 18 | patch and will need to be fixed in kexec-tools instead. | 26 | patch and will need to be fixed in kexec-tools instead. |
| 27 | |||
| 28 | Changes in v3: | ||
| 29 | - Round out nosave PFN ranges since the kernel does not use partial | ||
| 30 | pages | ||
| 31 | - Link to v2: https://lore.kernel.org/r/20250405-fix-e820-nosave-v2-1-d40dbe457c95@qtmlabs.xyz | ||
| 32 | |||
| 33 | Changes in v2: | ||
| 34 | - Updated author details | ||
| 35 | - Rewrote commit message | ||
| 36 | - Link to v1: https://lore.kernel.org/r/20250405-fix-e820-nosave-v1-1-162633199548@qtmlabs.xyz | ||
| 19 | --- | 37 | --- |
| 20 | arch/x86/kernel/e820.c | 17 ++++++++--------- | 38 | arch/x86/kernel/e820.c | 17 ++++++++--------- |
| 21 | 1 file changed, 8 insertions(+), 9 deletions(-) | 39 | 1 file changed, 8 insertions(+), 9 deletions(-) |
| 22 | 40 | ||
| 23 | diff --git a/arch/x86/kernel/e820.c b/arch/x86/kernel/e820.c | 41 | diff --git a/arch/x86/kernel/e820.c b/arch/x86/kernel/e820.c |
| ... | ... | ||
| 44 | + continue; | 62 | + continue; |
| 45 | 63 | ||
| 46 | - if (pfn >= limit_pfn) | 64 | - if (pfn >= limit_pfn) |
| 47 | - break; | 65 | - break; |
| 48 | + if (last_addr < entry->addr) | 66 | + if (last_addr < entry->addr) |
| 49 | + register_nosave_region(PFN_UP(last_addr), PFN_DOWN(entry->addr)); | 67 | + register_nosave_region(PFN_DOWN(last_addr), PFN_UP(entry->addr)); |
| 50 | + | 68 | + |
| 51 | + last_addr = entry->addr + entry->size; | 69 | + last_addr = entry->addr + entry->size; |
| 52 | } | 70 | } |
| 53 | + | 71 | + |
| 54 | + register_nosave_region(PFN_UP(last_addr), limit_pfn); | 72 | + register_nosave_region(PFN_DOWN(last_addr), limit_pfn); |
| 55 | } | 73 | } |
| 56 | 74 | ||
| 57 | #ifdef CONFIG_ACPI | 75 | #ifdef CONFIG_ACPI |
| 58 | 76 | ||
| 59 | --- | 77 | --- |
| 60 | base-commit: e48e99b6edf41c69c5528aa7ffb2daf3c59ee105 | 78 | base-commit: a8662bcd2ff152bfbc751cab20f33053d74d0963 |
| 61 | change-id: 20250405-fix-e820-nosave-c43779583abe | 79 | change-id: 20250405-fix-e820-nosave-f5cb985a9a61 |
| 62 | 80 | ||
| 63 | Best regards, | 81 | Best regards, |
| 64 | -- | 82 | -- |
| 65 | msizanoen <msizanoen@qtmlabs.xyz> | 83 | Myrrh Periwinkle <myrrhperiwinkle@qtmlabs.xyz> | diff view generated by jsdifflib |