user/sven/linux.git/arch/mips/kernel, branch v4.8.5

MIPS: Fix detection of unsupported highmem with cache aliases

2016-09-29T16:59:49Z

The paging_init() function contains code which detects that highmem is in use but unsupported due to dcache aliasing. However this code was ineffective because it was being run before the caches are probed, meaning that cpu_has_dc_aliases would always evaluate to false (unless a platform overrides it to a compile-time constant) and the detection of the unsupported case is never triggered. The kernel would then go on to attempt to use highmem & either hit coherency issues or trigger the BUG_ON in flush_kernel_dcache_page(). Fix this by running paging_init() later than cpu_cache_init(), such that the cpu_has_dc_aliases macro will evaluate correctly & the unsupported highmem case will be detected successfully. This then leads to a formerly hidden issue in that mem_init_free_highmem() will attempt to free all highmem pages, even though we're avoiding use of them & don't have valid page structs for them. This leads to an invalid pointer dereference & a TLB exception. Avoid this by skipping the loop in mem_init_free_highmem() if cpu_has_dc_aliases evaluates true. Signed-off-by: Paul Burton Cc: Rabin Vincent Cc: Matt Redfearn Cc: Jerome Marchand Cc: Alexander Sverdlin Cc: Aurelien Jarno Cc: Jaedon Shin Cc: Toshi Kani Cc: James Hogan Cc: Sergey Ryazanov Cc: Jonas Gorski Cc: Kirill A. Shutemov Cc: linux-mips@linux-mips.org Cc: linux-kernel@vger.kernel.org Patchwork: https://patchwork.linux-mips.org/patch/14184/ Signed-off-by: Ralf Baechle

MIPS: Fix BUILD_ROLLBACK_PROLOGUE for microMIPS

2016-09-29T16:59:49Z

When the kernel is built for microMIPS, branches targets need to be known to be microMIPS code in order to result in bit 0 of the PC being set. The branch target in the BUILD_ROLLBACK_PROLOGUE macro was simply the end of the macro, which may be pointing at padding rather than at code. This results in recent enough GNU linkers complaining like so: mips-img-linux-gnu-ld: arch/mips/built-in.o: .text+0x3e3c: Unsupported branch between ISA modes. mips-img-linux-gnu-ld: final link failed: Bad value Makefile:936: recipe for target 'vmlinux' failed make: *** [vmlinux] Error 1 Fix this by changing the branch target to be the start of the appropriate handler, skipping over any padding. Signed-off-by: Paul Burton Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/14019/ Signed-off-by: Ralf Baechle

MIPS: clear execution hazard after changing FTLB enable

2016-09-29T16:59:49Z

On current P-series cores from Imagination the FTLB can be enabled or disabled via a bit in the Config6 register, and an execution hazard is created by changing the value of bit. The ftlb_disable function already cleared that hazard but that does no good for other callers. Clear the hazard in the set_ftlb_enable function that creates it, and only for the cores where it applies. This has the effect of reverting c982c6d6c48b ("MIPS: cpu-probe: Remove cp0 hazard barrier when enabling the FTLB") which was incorrect. Signed-off-by: Paul Burton Fixes: c982c6d6c48b ("MIPS: cpu-probe: Remove cp0 hazard barrier when enabling the FTLB") Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/14023/ Signed-off-by: Ralf Baechle

MIPS: Configure FTLB after probing TLB sizes from config4

2016-09-29T16:59:49Z

On some cores (proAptiv, P5600) we make use of the sizes of the TLBs to determine the desired FTLB:VTLB write ratio. However set_ftlb_enable & thus calculate_ftlb_probability is called before decode_config4. This results in us calculating a probability based on zero sizes, and we end up setting FTLBP=3 for a 3:1 FTLB:VTLB write ratio in all cases. This will make abysmal use of the available FTLB resources in the affected cores. Fix this by configuring the FTLB probability after having decoded config4. However we do need to have enabled the FTLB before that point such that fields in config4 actually reflect that an FTLB is present. So set_ftlb_enable is now called twice, with flags indicating that it should configure the write probability only the second time. Signed-off-by: Paul Burton Fixes: cf0a8aa0226d ("MIPS: cpu-probe: Set the FTLB probability bit on supported cores") Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/14022/ Signed-off-by: Ralf Baechle

MIPS: Stop setting I6400 FTLBP

2016-09-29T16:59:49Z

The FTLBP field in Config7 for the I6400 is intended as chicken bits for debugging rather than as a field that software actually makes use of. For best performance, FTLBP should be left at its default value of 0 with all TLB writes hitting the FTLB by default. Additionally, since set_ftlb_enable is called from decode_configs before decode_config4 which determines the size of the TLBs, this was previously always setting FTLBP=3 for a 3:1 FTLB:VTLB write ratio which makes abysmal use of the available FTLB resources. This effectively reverts b0c4e1b79d8a ("MIPS: Set up FTLB probability for I6400"). Signed-off-by: Paul Burton Fixes: b0c4e1b79d8a ("MIPS: Set up FTLB probability for I6400") Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/14021/ Signed-off-by: Ralf Baechle

MIPS: uprobes: fix use of uninitialised variable

2016-09-29T16:59:49Z

arch_uprobe_pre_xol needs to emulate a branch if a branch instruction has been replaced with a breakpoint, but in fact an uninitialised local variable was passed to the emulator routine instead of the original instruction Signed-off-by: Marcin Nowakowski Fixes: 40e084a506eb ('MIPS: Add uprobes support.') Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/14300/ Signed-off-by: Ralf Baechle

MIPS: uprobes: remove incorrect set_orig_insn

2016-09-29T16:59:49Z

Generic kernel code implements a weak version of set_orig_insn that moves cached 'insn' from arch_uprobe to the original code location when the trap is removed. MIPS variant used arch_uprobe->orig_inst which was never initialised properly, so this code only inserted a nop instead of the original instruction. With that change orig_inst can also be safely removed. Signed-off-by: Marcin Nowakowski Fixes: 40e084a506eb ('MIPS: Add uprobes support.') Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/14299/ Signed-off-by: Ralf Baechle

MIPS: fix uretprobe implementation

2016-09-29T16:59:49Z

arch_uretprobe_hijack_return_addr should replace the return address for a call with a trampoline address. Signed-off-by: Marcin Nowakowski Fixes: 40e084a506eb ('MIPS: Add uprobes support.') Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/14298/ Signed-off-by: Ralf Baechle

MIPS: smp-cps: Avoid BUG() when offlining pre-r6 CPUs

2016-09-29T16:59:49Z

Commit 0d2808f338c7 ("MIPS: smp-cps: Add support for CPU hotplug of MIPSr6 processors") added a call to mips_cm_lock_other in order to lock the CPC in CPUs containing a version 3 or higher Coherence Manager, which use the general CM core other register, where previous CMs had a dedicated core other register for the CPC. A kernel BUG() is triggered, however, if mips_cm_lock_other is called with a VP other than 0 on a CPU with CM < 3, a condition introduced by 0d2808f338c7. Avoid the BUG() by always locking VP0 when locking the CPC, since the required register, cpc_stat_conf, is shared by all vps in a core. Fixes: 0d2808f338c7 ("MIPS: smp-cps: Add support for CPU hotplug...) Signed-off-by: Matt Redfearn Cc: Qais Yousef Cc: Masahiro Yamada Cc: James Hogan Cc: Paul Burton Cc: Andrew Morton Cc: linux-mips@linux-mips.org Cc: linux-kernel@vger.kernel.org Patchwork: https://patchwork.linux-mips.org/patch/14297/ Signed-off-by: Ralf Baechle

MIPS: SMP: Fix possibility of deadlock when bringing CPUs online

2016-09-24T23:43:52Z

This patch fixes the possibility of a deadlock when bringing up secondary CPUs. The deadlock occurs because the set_cpu_online() is called before synchronise_count_slave(). This can cause a deadlock if the boot CPU, having scheduled another thread, attempts to send an IPI to the secondary CPU, which it sees has been marked online. The secondary is blocked in synchronise_count_slave() waiting for the boot CPU to enter synchronise_count_master(), but the boot cpu is blocked in smp_call_function_many() waiting for the secondary to respond to it's IPI request. Fix this by marking the CPU online in cpu_callin_map and synchronising counters before declaring the CPU online and calculating the maps for IPIs. Signed-off-by: Matt Redfearn Reported-by: Justin Chen Tested-by: Justin Chen Cc: Florian Fainelli Cc: stable@vger.kernel.org # v4.1+ Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/14302/ Signed-off-by: Ralf Baechle