kernel.git/arch/mips/kernel/setup.c, branch linux-5.5.y

MIPS: Fix CONFIG_MIPS_CMDLINE_DTB_EXTEND handling

2020-03-18T06:19:12Z

commit 8e029eb0bcd6a7fab6dc9191152c085784c31ee6 upstream. The CONFIG_MIPS_CMDLINE_DTB_EXTEND option is used so that the kernel arguments provided in the 'bootargs' property in devicetree are extended with the kernel arguments provided by the bootloader. The code was broken, as it didn't actually take any of the kernel arguments provided in devicetree when that option was set. Fixes: 7784cac69735 ("MIPS: cmdline: Clean up boot_command_line initialization") Cc: stable@vger.kernel.org Signed-off-by: Paul Cercueil Signed-off-by: Thomas Bogendoerfer Signed-off-by: Greg Kroah-Hartman

MIPS: Loongson64: Rename CPU TYPES

2019-10-31T22:03:10Z

CPU_LOONGSON2 -> CPU_LOONGSON2EF CPU_LOONGSON3 -> CPU_LOONGSON64 As newer loongson-2 products (2G/2H/2K1000) can share kernel implementation with loongson-3 while 2E/2F are less similar with other LOONGSON64 products. Signed-off-by: Jiaxun Yang Signed-off-by: Paul Burton Cc: linux-mips@vger.kernel.org Cc: chenhc@lemote.com Cc: paul.burton@mips.com

MIPS: Make builtin_cmdline const & variable length

2019-10-12T20:44:24Z

We have no need for the builtin_cmdline array to be fixed at the length of COMMAND_LINE_SIZE - we'll only copy out the string it contains up to its NULL terminator anyway, and cap the size at COMMAND_LINE_SIZE when copying into or concatenating with boot_command_line. The string value is also constant, so we can declare it as such to place it in the .init.rodata section. Signed-off-by: Paul Burton Cc: linux-mips@vger.kernel.org

MIPS: Fix CONFIG_OF_EARLY_FLATTREE=n builds

2019-10-12T20:44:23Z

Configurations with CONFIG_OF_EARLY_FLATTREE=n fail to build since commit 7784cac69735 ("MIPS: cmdline: Clean up boot_command_line initialization") because of_scan_flat_dt() & of_scan_flat_dt() are not defined in these configurations. Fix this by #ifdef'ing the affected code... Signed-off-by: Paul Burton Fixes: 7784cac69735 ("MIPS: cmdline: Clean up boot_command_line initialization") Reported-by: kbuild test robot Cc: linux-mips@vger.kernel.org

MIPS: Always define builtin_cmdline

2019-10-12T20:44:22Z

Commit 7784cac69735 ("MIPS: cmdline: Clean up boot_command_line initialization") made use of builtin_cmdline conditional upon plain C if statements rather than preprocessor #ifdef's. This caused build failures for configurations with CONFIG_CMDLINE_BOOL=n where builtin_cmdline wasn't defined, for example: arch/mips/kernel/setup.c: In function 'bootcmdline_init': >> arch/mips/kernel/setup.c:582:30: error: 'builtin_cmdline' undeclared (first use in this function); did you mean 'builtin_driver'? strlcpy(boot_command_line, builtin_cmdline, COMMAND_LINE_SIZE); ^~~~~~~~~~~~~~~ builtin_driver arch/mips/kernel/setup.c:582:30: note: each undeclared identifier is reported only once for each function it appears in Fix this by defining builtin_cmdline as an empty string in the affected configurations. All of the paths that use it should be optimized out anyway so the data itself gets optimized away too. Signed-off-by: Paul Burton Fixes: 7784cac69735 ("MIPS: cmdline: Clean up boot_command_line initialization") Reported-by: kbuild test robot Reported-by: Nathan Chancellor Cc: linux-mips@vger.kernel.org

MIPS: cmdline: Clean up boot_command_line initialization

2019-10-10T18:56:43Z

Our current code to initialize boot_command_line is a mess. Some of this is due to the addition of too many options over the years, and some of this is due to workarounds for early_init_dt_scan_chosen() performing actions specific to options from other architectures that probably shouldn't be in generic code. Clean this up by introducing a new bootcmdline_init() function that simplifies the initialization somewhat. The major changes are: - Because bootcmdline_init() is a function it can return early in the CONFIG_CMDLINE_OVERRIDE case. - We clear boot_command_line rather than inheriting whatever early_init_dt_scan_chosen() may have left us. This means we no longer need to set boot_command_line to a space character in an attempt to prevent early_init_dt_scan_chosen() from copying CONFIG_CMDLINE into boot_command_line without us knowing about it. - Indirection via USE_PROM_CMDLINE, USE_DTB_CMDLINE, EXTEND_WITH_PROM & BUILTIN_EXTEND_WITH_PROM macros is removed; they seemingly served only to obfuscate the code. - The logic is cleaner, clearer & commented. Two minor drawbacks of this approach are: 1) We call of_scan_flat_dt(), which means we scan through the DT again. The overhead is fairly minimal & shouldn't be noticeable. 2) cmdline_scan_chosen() duplicates a small amount of the logic from early_init_dt_scan_chosen(). Alternatives might be to allow the generic FDT code to keep & expose a copy of the arguments taken from the /chosen node's bootargs property, or to introduce a function like early_init_dt_scan_chosen() that retrieves them without modification to handle CONFIG_CMDLINE. Neither of these sounds particularly cleaner though, and this way we at least keep the extra work in arch/mips. Signed-off-by: Paul Burton Cc: linux-mips@vger.kernel.org

MIPS: init: Prevent adding memory before PHYS_OFFSET

2019-10-02T21:11:30Z

On some SGI machines (IP28 and IP30) a small region of memory is mirrored to pyhsical address 0 for exception vectors while rest of the memory is reachable at a higher physical address. ARC PROM marks this region as reserved, but with commit a94e4f24ec83 ("MIPS: init: Drop boot_mem_map") this chunk is used, when searching for start of ram, which breaks at least IP28 and IP30 machines. To fix this add_region_memory() checks for start address < PHYS_OFFSET and ignores these chunks. Fixes: a94e4f24ec83 ("MIPS: init: Drop boot_mem_map") Signed-off-by: Thomas Bogendoerfer Signed-off-by: Paul Burton Cc: Ralf Baechle Cc: James Hogan Cc: linux-mips@vger.kernel.org Cc: linux-kernel@vger.kernel.org

MIPS: init: Fix reservation of memory between PHYS_OFFSET and mem start

2019-10-02T21:10:16Z

Fix calculation of the size for reserving memory between PHYS_OFFSET and real memory start. Fixes: a94e4f24ec83 ("MIPS: init: Drop boot_mem_map") Signed-off-by: Thomas Bogendoerfer Signed-off-by: Paul Burton Cc: Ralf Baechle Cc: James Hogan Cc: linux-mips@vger.kernel.org Cc: linux-kernel@vger.kernel.org

mips: avoid explicit UB in assignment of mips_io_port_base

2019-08-24T14:10:58Z

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

MIPS: Fix build with CONFIG_PROC_VMCORE=y

2019-08-23T17:02:49Z

Commit a94e4f24ec83 ("MIPS: init: Drop boot_mem_map") introduced a reference to a non-existant "end" field in struct memblock_region. Replace it with a sum of the base & size fields to fix builds with CONFIG_PROC_VMCORE=y. Reported-by: kbuild test robot Signed-off-by: Paul Burton