| Age | Commit message (Collapse) | Author | Files | Lines | |
|---|---|---|---|---|---|
| 2018-08-21 | MIPS: lib: Provide MIPS64r6 __multi3() for GCC < 7 | Paul Burton | 1 | -3/+3 | |
| Some versions of GCC suboptimally generate calls to the __multi3() intrinsic for MIPS64r6 builds, resulting in link failures due to the missing function: LD vmlinux.o MODPOST vmlinux.o kernel/bpf/verifier.o: In function `kmalloc_array': include/linux/slab.h:631: undefined reference to `__multi3' fs/select.o: In function `kmalloc_array': include/linux/slab.h:631: undefined reference to `__multi3' ... We already have a workaround for this in which we provide the instrinsic, but we do so selectively for GCC 7 only. Unfortunately the issue occurs with older GCC versions too - it has been observed with both GCC 5.4.0 & GCC 6.4.0. MIPSr6 support was introduced in GCC 5, so all major GCC versions prior to GCC 8 are affected and we extend our workaround accordingly to all MIPS64r6 builds using GCC versions older than GCC 8. Signed-off-by: Paul Burton <[email protected]> Reported-by: Vladimir Kondratiev <[email protected]> Fixes: ebabcf17bcd7 ("MIPS: Implement __multi3 for GCC7 MIPS64r6 builds") Patchwork: https://patchwork.linux-mips.org/patch/20297/ Cc: James Hogan <[email protected]> Cc: Ralf Baechle <[email protected]> Cc: [email protected] Cc: [email protected] # 4.15+ | |||||
| 2018-01-11 | MIPS: Implement __multi3 for GCC7 MIPS64r6 builds | James Hogan | 1 | -0/+54 | |
| GCC7 is a bit too eager to generate suboptimal __multi3 calls (128bit multiply with 128bit result) for MIPS64r6 builds, even in code which doesn't explicitly use 128bit types, such as the following: unsigned long func(unsigned long a, unsigned long b) { return a > (~0UL) / b; } Which GCC rearanges to: return (unsigned __int128)a * (unsigned __int128)b > 0xffffffffffffffff; Therefore implement __multi3, but only for MIPS64r6 with GCC7 as under normal circumstances we wouldn't expect any calls to __multi3 to be generated from kernel code. Reported-by: Thomas Petazzoni <[email protected]> Signed-off-by: James Hogan <[email protected]> Tested-by: Waldemar Brodkorb <[email protected]> Cc: Ralf Baechle <[email protected]> Cc: Maciej W. Rozycki <[email protected]> Cc: Matthew Fortune <[email protected]> Cc: Florian Fainelli <[email protected]> Cc: [email protected] Patchwork: https://patchwork.linux-mips.org/patch/17890/ | |||||