bybrooklyn/linux
1
0
Fork 0
mirror of https://github.com/torvalds/linux.git synced 2026-04-18 14:53:58 -04:00
Code Issues Packages Projects Releases Wiki Activity

Merge tag 'mips_4.19' of git://git.kernel.org/pub/scm/linux/kernel/git/mips/linux

Browse Source 
Pull MIPS updates from Paul Burton:
 "Here are the main MIPS changes for 4.19.

  An overview of the general architecture changes:

   - Massive DMA ops refactoring from Christoph Hellwig (huzzah for
     deleting crufty code!).

   - We introduce NT_MIPS_DSP & NT_MIPS_FP_MODE ELF notes &
     corresponding regsets to expose DSP ASE & floating point mode state
     respectively, both for live debugging & core dumps.

   - We better optimize our code by hard-coding cpu_has_* macros at
     compile time where their values are known due to the ISA revision
     that the kernel build is targeting.

   - The EJTAG exception handler now better handles SMP systems, where
     it was previously possible for CPUs to clobber a register value
     saved by another CPU.

   - Our implementation of memset() gained a couple of fixes for MIPSr6
     systems to return correct values in some cases where stores fault.

   - We now implement ioremap_wc() using the uncached-accelerated cache
     coherency attribute where supported, which is detected during boot,
     and fall back to plain uncached access where necessary. The
     MIPS-specific (and unused in tree) ioremap_uncached_accelerated() &
     ioremap_cacheable_cow() are removed.

   - The prctl(PR_SET_FP_MODE, ...) syscall is better supported for SMP
     systems by reworking the way we ensure remote CPUs that may be
     running threads within the affected process switch mode.

   - Systems using the MIPS Coherence Manager will now set the
     MIPS_IC_SNOOPS_REMOTE flag to avoid some unnecessary cache
     maintenance overhead when flushing the icache.

   - A few fixes were made for building with clang/LLVM, which now
     sucessfully builds kernels for many of our platforms.

   - Miscellaneous cleanups all over.

  And some platform-specific changes:

   - ar7 gained stubs for a few clock API functions to fix build
     failures for some drivers.

   - ath79 gained support for a few new SoCs, a few fixes & better
     gpio-keys support.

   - Ci20 now exposes its SPI bus using the spi-gpio driver.

   - The generic platform can now auto-detect a suitable value for
     PHYS_OFFSET based upon the memory map described by the device tree,
     allowing us to avoid wasting memory on page book-keeping for
     systems where RAM starts at a non-zero physical address.

   - Ingenic systems using the jz4740 platform code now link their
     vmlinuz higher to allow for kernels of a realistic size.

   - Loongson32 now builds the kernel targeting MIPSr1 rather than
     MIPSr2 to avoid CPU errata.

   - Loongson64 gains a couple of fixes, a workaround for a write
     buffering issue & support for the Loongson 3A R3.1 CPU.

   - Malta now uses the piix4-poweroff driver to handle powering down.

   - Microsemi Ocelot gained support for its SPI bus & NOR flash, its
     second MDIO bus and can now be supported by a FIT/.itb image.

   - Octeon saw a bunch of header cleanups which remove a lot of
     duplicate or unused code"

* tag 'mips_4.19' of git://git.kernel.org/pub/scm/linux/kernel/git/mips/linux: (123 commits)
  MIPS: Remove remnants of UASM_ISA
  MIPS: netlogic: xlr: Remove erroneous check in nlm_fmn_send()
  MIPS: VDSO: Force link endianness
  MIPS: Always specify -EB or -EL when using clang
  MIPS: Use dins to simplify __write_64bit_c0_split()
  MIPS: Use read-write output operand in __write_64bit_c0_split()
  MIPS: Avoid using array as parameter to write_c0_kpgd()
  MIPS: vdso: Allow clang's --target flag in VDSO cflags
  MIPS: genvdso: Remove GOT checks
  MIPS: Remove obsolete MIPS checks for DST node "chosen@0"
  MIPS: generic: Remove input symbols from defconfig
  MIPS: Delete unused code in linux32.c
  MIPS: Remove unused sys_32_mmap2
  MIPS: Remove nabi_no_regargs
  mips: dts: mscc: enable spi and NOR flash support on ocelot PCB123
  mips: dts: mscc: Add spi on Ocelot
  MIPS: Loongson: Merge load addresses
  MIPS: Loongson: Set Loongson32 to MIPS32R1
  MIPS: mscc: ocelot: add interrupt controller properties to GPIO controller
  MIPS: generic: Select MIPS_AUTO_PFN_OFFSET
  ...
This commit is contained in:
Linus Torvalds
2018-08-13 19:24:32 -07:00
parent 2280a5360e 22f20a1103
commit e5a32b5b21
178 changed files with 2959 additions and 12254 deletions
Download Patch File Download Diff File Expand all files Collapse all files

80
arch/mips/kernel/process.c
View File

@@ -30,6 +30,7 @@
#include <linux/random.h>
#include <linux/prctl.h>
#include <linux/nmi.h>
#include <linux/cpu.h>
#include <asm/asm.h>
#include <asm/bootinfo.h>
@@ -706,19 +707,25 @@ int mips_get_process_fp_mode(struct task_struct *task)
return value;
}
static void prepare_for_fp_mode_switch(void *info)
static long prepare_for_fp_mode_switch(void *unused)
{
struct mm_struct *mm = info;
if (current->mm == mm)
lose_fpu(1);
/*
* This is icky, but we use this to simply ensure that all CPUs have
* context switched, regardless of whether they were previously running
* kernel or user code. This ensures that no CPU currently has its FPU
* enabled, or is about to attempt to enable it through any path other
* than enable_restore_fp_context() which will wait appropriately for
* fp_mode_switching to be zero.
*/
return 0;
}
int mips_set_process_fp_mode(struct task_struct *task, unsigned int value)
{
const unsigned int known_bits = PR_FP_MODE_FR | PR_FP_MODE_FRE;
struct task_struct *t;
int max_users;
struct cpumask process_cpus;
int cpu;
/* If nothing to change, return right away, successfully. */
if (value == mips_get_process_fp_mode(task))
@@ -751,35 +758,7 @@ int mips_set_process_fp_mode(struct task_struct *task, unsigned int value)
if (!(value & PR_FP_MODE_FR) && raw_cpu_has_fpu && cpu_has_mips_r6)
return -EOPNOTSUPP;
/* Proceed with the mode switch */
preempt_disable();
/* Save FP & vector context, then disable FPU & MSA */
if (task->signal == current->signal)
lose_fpu(1);
/* Prevent any threads from obtaining live FP context */
atomic_set(&task->mm->context.fp_mode_switching, 1);
smp_mb__after_atomic();
/*
* If there are multiple online CPUs then force any which are running
* threads in this process to lose their FPU context, which they can't
* regain until fp_mode_switching is cleared later.
*/
if (num_online_cpus() > 1) {
/* No need to send an IPI for the local CPU */
max_users = (task->mm == current->mm) ? 1 : 0;
if (atomic_read(&current->mm->mm_users) > max_users)
smp_call_function(prepare_for_fp_mode_switch,
(void *)current->mm, 1);
}
/*
* There are now no threads of the process with live FP context, so it
* is safe to proceed with the FP mode switch.
*/
/* Indicate the new FP mode in each thread */
for_each_thread(task, t) {
/* Update desired FP register width */
if (value & PR_FP_MODE_FR) {
@@ -796,9 +775,34 @@ int mips_set_process_fp_mode(struct task_struct *task, unsigned int value)
clear_tsk_thread_flag(t, TIF_HYBRID_FPREGS);
}
/* Allow threads to use FP again */
atomic_set(&task->mm->context.fp_mode_switching, 0);
preempt_enable();
/*
* We need to ensure that all threads in the process have switched mode
* before returning, in order to allow userland to not worry about
* races. We can do this by forcing all CPUs that any thread in the
* process may be running on to schedule something else - in this case
* prepare_for_fp_mode_switch().
*
* We begin by generating a mask of all CPUs that any thread in the
* process may be running on.
*/
cpumask_clear(&process_cpus);
for_each_thread(task, t)
cpumask_set_cpu(task_cpu(t), &process_cpus);
/*
* Now we schedule prepare_for_fp_mode_switch() on each of those CPUs.
*
* The CPUs may have rescheduled already since we switched mode or
* generated the cpumask, but that doesn't matter. If the task in this
* process is scheduled out then our scheduling
* prepare_for_fp_mode_switch() will simply be redundant. If it's
* scheduled in then it will already have picked up the new FP mode
* whilst doing so.
*/
get_online_cpus();
for_each_cpu_and(cpu, &process_cpus, cpu_online_mask)
work_on_cpu(cpu, prepare_for_fp_mode_switch, NULL);
put_online_cpus();
wake_up_var(&task->mm->context.fp_mode_switching);