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Colin Ian Kinggregkh
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perf/x86/intel/uncore: Fix integer overflow on 23 bit left shift of a u32
[ Upstream commit 0b3a873 ] The u32 variable pci_dword is being masked with 0x1fffffff and then left shifted 23 places. The shift is a u32 operation,so a value of 0x200 or more in pci_dword will overflow the u32 and only the bottow 32 bits are assigned to addr. I don't believe this was the original intent. Fix this by casting pci_dword to a resource_size_t to ensure no overflow occurs. Note that the mask and 12 bit left shift operation does not need this because the mask SNR_IMC_MMIO_MEM0_MASK and shift is always a 32 bit value. Fixes: ee49532 ("perf/x86/intel/uncore: Add IMC uncore support for Snow Ridge") Addresses-Coverity: ("Unintentional integer overflow") Signed-off-by: Colin Ian King <colin.king@canonical.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Reviewed-by: Kan Liang <kan.liang@linux.intel.com> Link: https://lore.kernel.org/r/20210706114553.28249-1-colin.king@canonical.com Signed-off-by: Sasha Levin <sashal@kernel.org>
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arch/x86/events/intel/uncore_snbep.c

Lines changed: 1 addition & 1 deletion
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@@ -4669,7 +4669,7 @@ static void __snr_uncore_mmio_init_box(struct intel_uncore_box *box,
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return;
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pci_read_config_dword(pdev, SNR_IMC_MMIO_BASE_OFFSET, &pci_dword);
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addr = (pci_dword & SNR_IMC_MMIO_BASE_MASK) << 23;
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addr = ((resource_size_t)pci_dword & SNR_IMC_MMIO_BASE_MASK) << 23;
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pci_read_config_dword(pdev, mem_offset, &pci_dword);
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addr |= (pci_dword & SNR_IMC_MMIO_MEM0_MASK) << 12;

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