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Filename Latest commit message Latest commit date
Nathan Chancellor 684bddacf1 KVM: PPC: Book3S HV: Workaround high stack usage with clang
commit 51696f39cbee5bb684e7959c0c98b5f54548aa34 upstream.

LLVM does not emit optimal byteswap assembly, which results in high
stack usage in kvmhv_enter_nested_guest() due to the inlining of
byteswap_pt_regs(). With LLVM 12.0.0:

arch/powerpc/kvm/book3s_hv_nested.c:289:6: error: stack frame size of
2512 bytes in function 'kvmhv_enter_nested_guest' [-Werror,-Wframe-larger-than=]
long kvmhv_enter_nested_guest(struct kvm_vcpu *vcpu)
     ^
1 error generated.

While this gets fixed in LLVM, mark byteswap_pt_regs() as
noinline_for_stack so that it does not get inlined and break the build
due to -Werror by default in arch/powerpc/. Not inlining saves
approximately 800 bytes with LLVM 12.0.0:

arch/powerpc/kvm/book3s_hv_nested.c:290:6: warning: stack frame size of
1728 bytes in function 'kvmhv_enter_nested_guest' [-Wframe-larger-than=]
long kvmhv_enter_nested_guest(struct kvm_vcpu *vcpu)
     ^
1 warning generated.

Cc: stable@vger.kernel.org # v4.20+
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://github.com/ClangBuiltLinux/linux/issues/1292
Link: https://bugs.llvm.org/show_bug.cgi?id=49610
Link: https://lore.kernel.org/r/202104031853.vDT0Qjqj-lkp@intel.com/
Link: https://gist.github.com/ba710e3703bf45043a31e2806c843ffd
Link: https://lore.kernel.org/r/20210621182440.990242-1-nathan@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-07-14 16:53:05 +02:00
arch KVM: PPC: Book3S HV: Workaround high stack usage with clang 2021-07-14 16:53:05 +02:00
block blk-mq: Swap two calls in blk_mq_exit_queue() 2021-05-19 10:08:30 +02:00
certs certs: Move load_system_certificate_list to a common function 2021-06-30 08:47:55 -04:00
crypto crypto: rng - fix crypto_rng_reset() refcounting when !CRYPTO_STATS 2021-05-11 14:04:15 +02:00
Documentation mm/slub: clarify verification reporting 2021-06-23 14:41:30 +02:00
drivers perf/smmuv3: Don't trample existing events with global filter 2021-07-14 16:53:05 +02:00
fs ext4: use ext4_grp_locked_error in mb_find_extent 2021-07-14 16:53:03 +02:00
include certs: Add EFI_CERT_X509_GUID support for dbx entries 2021-06-30 08:47:55 -04:00
init kbuild: add CONFIG_LD_IS_LLD 2021-06-30 08:47:44 -04:00
ipc
kernel mm, futex: fix shared futex pgoff on shmem huge page 2021-06-30 08:47:55 -04:00
lib iov_iter_fault_in_readable() should do nothing in xarray case 2021-07-14 16:53:01 +02:00
LICENSES
mm mm, futex: fix shared futex pgoff on shmem huge page 2021-06-30 08:47:55 -04:00
net SUNRPC: Should wake up the privileged task firstly. 2021-07-14 16:53:05 +02:00
samples samples: vfio-mdev: fix error handing in mdpy_fb_probe() 2021-06-10 13:37:03 +02:00
scripts recordmcount: Correct st_shndx handling 2021-06-30 08:47:49 -04:00
security x86/efi: remove unused variables 2021-07-07 08:22:58 -04:00
sound ALSA: hda/realtek: Apply LED fixup for HP Dragonfly G1, too 2021-07-14 16:52:59 +02:00
tools KVM: selftests: Fix kvm_check_cap() assertion 2021-06-30 08:47:49 -04:00
usr
virt KVM: do not allow mapping valid but non-reference-counted pages 2021-06-30 08:47:50 -04:00
.clang-format
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.gitignore
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COPYING
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MAINTAINERS
Makefile Linux 5.4.131 2021-07-11 12:52:08 +02:00
README

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.