kernel/linux.git/arch/mips/include/asm/io.h, branch linux-4.4.y

mips: avoid explicit UB in assignment of mips_io_port_base

2020-01-29T09:21:47+00:00

[ Upstream commit 12051b318bc3ce5b42d6d786191008284b067d83 ] The code in question is modifying a variable declared const through pointer manipulation. Such code is explicitly undefined behavior, and is the lone issue preventing malta_defconfig from booting when built with Clang: If an attempt is made to modify an object defined with a const-qualified type through use of an lvalue with non-const-qualified type, the behavior is undefined. LLVM is removing such assignments. A simple fix is to not declare variables const that you plan on modifying. Limiting the scope would be a better method of preventing unwanted writes to such a variable. Further, the code in question mentions "compiler bugs" without any links to bug reports, so it is difficult to know if the issue is resolved in GCC. The patch was authored in 2006, which would have been GCC 4.0.3 or 4.1.1. The minimal supported version of GCC in the Linux kernel is currently 4.6. For what its worth, there was UB before the commit in question, it just added a barrier and got lucky IRT codegen. I don't think there's any actual compiler bugs related, just runtime bugs due to UB. Link: https://github.com/ClangBuiltLinux/linux/issues/610 Fixes: 966f4406d903 ("[MIPS] Work around bad code generation for .") Reported-by: Nathan Chancellor Debugged-by: Nathan Chancellor Suggested-by: Eli Friedman Signed-off-by: Nick Desaulniers Reviewed-by: Nathan Chancellor Tested-by: Nathan Chancellor Signed-off-by: Paul Burton Cc: ralf@linux-mips.org Cc: jhogan@kernel.org Cc: Maciej W. Rozycki Cc: Hassan Naveed Cc: Stephen Kitt Cc: Serge Semin Cc: Mike Rapoport Cc: Andrew Morton Cc: Michal Hocko Cc: linux-mips@vger.kernel.org Cc: linux-kernel@vger.kernel.org Cc: clang-built-linux@googlegroups.com Signed-off-by: Sasha Levin

MIPS: Fix ISA virt/bus conversion for non-zero PHYS_OFFSET

2018-09-19T20:48:58+00:00

[ Upstream commit 0494d7ffdcebc6935410ea0719b24ab626675351 ] isa_virt_to_bus() & isa_bus_to_virt() claim to treat ISA bus addresses as being identical to physical addresses, but they fail to do so in the presence of a non-zero PHYS_OFFSET. Correct this by having them use virt_to_phys() & phys_to_virt(), which consolidates the calculations to one place & ensures that ISA bus addresses do indeed match physical addresses. Signed-off-by: Paul Burton Patchwork: https://patchwork.linux-mips.org/patch/20047/ Cc: James Hogan Cc: Ralf Baechle Cc: linux-mips@linux-mips.org Cc: Vladimir Kondratiev Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

MIPS: io: Add barrier after register read in inX()

2018-07-03T09:21:30+00:00

commit 18f3e95b90b28318ef35910d21c39908de672331 upstream. While a barrier is present in the outX() functions before the register write, a similar barrier is missing in the inX() functions after the register read. This could allow memory accesses following inX() to observe stale data. This patch is very similar to commit a1cc7034e33d12dc1 ("MIPS: io: Add barrier after register read in readX()"). Because war_io_reorder_wmb() is both used by writeX() and outX(), if readX() need a barrier then so does inX(). Cc: stable@vger.kernel.org Signed-off-by: Huacai Chen Patchwork: https://patchwork.linux-mips.org/patch/19516/ Signed-off-by: Paul Burton Cc: James Hogan Cc: linux-mips@linux-mips.org Cc: Fuxin Zhang Cc: Zhangjin Wu Cc: Huacai Chen Signed-off-by: Greg Kroah-Hartman

MIPS: Define ioremap_uc

2015-10-06T11:19:25+00:00

All architectures must now define ioremap_uc(), but MIPS currently only has ioremap_nocache(). Fixes: 4c73e8926623 ("arch/*/io.h: Add ioremap_uc() to all architectures") Signed-off-by: Ben Hutchings Cc: Luis R. Rodriguez Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/11263/ Signed-off-by: Ralf Baechle

MIPS: Replace use of phys_t with phys_addr_t.

2014-11-24T21:47:31+00:00

Signed-off-by: Ralf Baechle

MIPS: Fix gigaton of warning building with microMIPS.

2014-03-31T16:17:12+00:00

With binutils 2.24 the attempt to switch with microMIPS mode to MIPS III mode through .set mips3 results in *lots* of warnings like {standard input}: Assembler messages: {standard input}:397: Warning: the 64-bit MIPS architecture does not support the `smartmips' extension during a kernel build. Fixed by using .set arch=r4000 instead. This breaks support for building the kernel with binutils 2.13 which was supported for 32 bit kernels only anyway and 2.14 which was a bad vintage for MIPS anyway. Signed-off-by: Ralf Baechle

MIPS: Extend DMA_MAYBE_COHERENT logic to DMA_NONCOHERENT use

2014-03-26T22:09:20+00:00

Setting DMA_MAYBE_COHERENT gives a platform the opportunity to select use of cache ops at boot. Signed-off-by: Manuel Lauss Cc: Linux-MIPS Patchwork: https://patchwork.linux-mips.org/patch/6575/ Signed-off-by: Ralf Baechle

MIPS: define write{b,w,l,q}_relaxed

2013-07-01T13:10:59+00:00

MIPS does define read{b,w,l,q}_relaxed but does not define their write counterparts: write{b,w,l,q}_relaxed. This patch adds the missing definitions for the write*_relaxed I/O accessors. Signed-off-by: Florian Fainelli Acked-by: John Crispin Cc: linux-mips@linux-mips.org Cc: cernekee@gmail.com Cc: jogo@openwrt.org Patchwork: https://patchwork.linux-mips.org/patch/5352/ Signed-off-by: Ralf Baechle

MIPS: Expose missing pci_io{map,unmap} declarations

2013-07-01T13:10:59+00:00

The GENERIC_PCI_IOMAP does not depend on CONFIG_PCI so move it to the CONFIG_MIPS symbol so it's always selected for MIPS. This fixes the missing pci_iomap declaration for MIPS. Moreover, the pci_iounmap function was not defined in the io.h header file if the CONFIG_PCI symbol is not set, but it should since MIPS is not using CONFIG_GENERIC_IOMAP. This fixes the following problem on a allyesconfig: drivers/net/ethernet/3com/3c59x.c:1031:2: error: implicit declaration of function 'pci_iomap' [-Werror=implicit-function-declaration] drivers/net/ethernet/3com/3c59x.c:1044:3: error: implicit declaration of function 'pci_iounmap' [-Werror=implicit-function-declaration] Signed-off-by: Markos Chandras Acked-by: Steven J. Hill Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/5478/ Signed-off-by: Ralf Baechle

MIPS: Make virt_to_phys() work for all unmapped addresses.

2013-05-17T18:36:15+00:00

As reported: This problem was discovered when doing BGP traffic with the TCP MD5 option activated, where the following call chain caused a crash: * tcp_v4_rcv * tcp_v4_timewait_ack * tcp_v4_send_ack -> follow stack variable rep.th * tcp_v4_md5_hash_hdr * tcp_md5_hash_header * sg_init_one * sg_set_buf * virt_to_page I noticed that tcp_v4_send_reset uses a similar stack variable and also calls tcp_v4_md5_hash_hdr, so it has the same problem. The networking core can indirectly call virt_to_phys() on stack addresses, if this is done from PID 0, the stack will usually be in CKSEG0, so virt_to_phys() needs to work there as well Signed-off-by: David Daney Cc: linux-mips@linux-mips.org Cc: Jiang Liu Cc: eunb.song@samsung.com Cc: linux-kernel@vger.kernel.org Patchwork: https://patchwork.linux-mips.org/patch/5220/ Signed-off-by: Ralf Baechle