linux/arch/arm/kernel/entry-common.S, branch v4.5

Merge branches 'cleanup', 'fixes', 'misc', 'omap-barrier' and 'uaccess' into for-linus

2015-09-03T14:28:37Z

ARM: entry: provide uaccess assembly macro hooks

2015-08-26T19:27:02Z

Provide hooks into the kernel entry and exit paths to permit control of userspace visibility to the kernel. The intended use is: - on entry to kernel from user, uaccess_disable will be called to disable userspace visibility - on exit from kernel to user, uaccess_enable will be called to enable userspace visibility - on entry from a kernel exception, uaccess_save_and_disable will be called to save the current userspace visibility setting, and disable access - on exit from a kernel exception, uaccess_restore will be called to restore the userspace visibility as it was before the exception occurred. These hooks allows us to keep userspace visibility disabled for the vast majority of the kernel, except for localised regions where we want to explicitly access userspace. Signed-off-by: Russell King

ARM: entry: ensure that IRQs are enabled when calling syscall_trace_exit()

2015-08-25T09:32:50Z

The audit code looks like it's been written to cope with being called with IRQs enabled. However, it's unclear whether IRQs should be enabled or disabled when calling the syscall tracing infrastructure. Right now, sometimes we call this with IRQs enabled, and other times with IRQs disabled. Opt for IRQs being enabled for consistency. Acked-by: Will Deacon Signed-off-by: Russell King

ARM: entry: efficiency cleanups

2015-08-25T09:32:48Z

Make the "fast" syscall return path fast again. The addition of IRQ tracing and context tracking has made this path grossly inefficient. We can do much better if these options are enabled if we save the syscall return code on the stack - we then don't need to save a bunch of registers around every single callout to C code. Acked-by: Will Deacon Signed-off-by: Russell King

ARM: 8409/1: Mark ret_fast_syscall as a function

2015-08-07T18:57:02Z

ret_fast_syscall runs when user space makes a syscall. However it needs to be marked as such so the ELF information is correct. Before it was: 101: 8000f300 0 NOTYPE LOCAL DEFAULT 2 ret_fast_syscall But with this change it correctly shows as: 101: 8000f300 96 FUNC LOCAL DEFAULT 2 ret_fast_syscall I see this function when using perf to unwind call stacks from kernel space to user space. Without this change I would need to add some special case logic when using the vmlinux ELF information. Signed-off-by: Drew Richardson Acked-by: Nicolas Pitre Signed-off-by: Russell King

Merge branch 'bsym' into for-next

2015-06-12T20:18:38Z

Conflicts: arch/arm/kernel/head.S

ARM: fix missing syscall trace exit

2015-05-15T10:06:35Z

Josh Stone reports: I've discovered a case where both arm and arm64 will miss a ptrace syscall-exit that they should report. If the syscall is entered without TIF_SYSCALL_TRACE set, then it goes on the fast path. It's then possible to have TIF_SYSCALL_TRACE added in the middle of the syscall, but ret_fast_syscall doesn't check this flag again. Fix this by always checking for a syscall trace in the fast exit path. Reported-by: Josh Stone Signed-off-by: Russell King

ARM: replace BSYM() with badr assembly macro

2015-05-08T16:33:50Z

BSYM() was invented to allow us to work around a problem with the assembler, where local symbols resolved by the assembler for the 'adr' instruction did not take account of their ISA. Since we don't want BSYM() used elsewhere, replace BSYM() with a new macro 'badr', which is like the 'adr' pseudo-op, but with the BSYM() mechanics integrated into it. This ensures that the BSYM()-ification is only used in conjunction with 'adr'. Acked-by: Dave Martin Acked-by: Nicolas Pitre Signed-off-by: Russell King

ARM: move ftrace assembly code to separate file

2014-11-21T15:25:01Z

The ftrace assembly code doesn't need to live in entry-common.S and be surrounded with #ifdef CONFIG_FUNCTION_TRACER. Instead, move it to its own file and conditionally assemble it. Tested-by: Felipe Balbi Signed-off-by: Russell King

ARM: Avoid writing to control register on every exception

2014-09-26T13:39:54Z

If we are not changing the control register value, avoid writing to it. Writes to the control register can be very expensive, taking around a hundred cycles or so. Signed-off-by: Russell King