linux/arch/powerpc
Christophe Leroy 88670fdb26 powerpc/ftrace: No need to read LR from stack in _mcount()
All functions calling _mcount do it exactly the same way, with the
following sequence of instructions:

	c07de788:       7c 08 02 a6     mflr    r0
	c07de78c:       90 01 00 04     stw     r0,4(r1)
	c07de790:       4b 84 13 65     bl      c001faf4 <_mcount>

Allthough LR is pushed on stack, it is still in r0 while entering
_mcount().

Function arguments are in r3-r10, so r11 and r12 are still available
at that point.

Do like PPC64 and use r12 to move LR into CTR, so that r0 is preserved
and doesn't need to be restored from the stack.

While at it, bring back the EXPORT_SYMBOL at the end of _mcount.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/24a3ba7db388537c44a038026f926d885372e6d3.1635423081.git.christophe.leroy@csgroup.eu
2021-11-29 22:49:29 +11:00
..
boot powerpc updates for 5.16 2021-11-05 08:15:46 -07:00
configs powerpc/pseries: delete scanlog 2021-11-25 11:25:33 +11:00
crypto crypto: powepc/sha1 - remove unneeded semicolon 2021-03-07 15:13:14 +11:00
include powerpc: Mark probe_machine() __init and static 2021-11-29 22:49:26 +11:00
kernel powerpc/ftrace: No need to read LR from stack in _mcount() 2021-11-29 22:49:29 +11:00
kexec powerpc/machdep: Remove stale functions from ppc_md structure 2021-10-22 15:22:05 +11:00
kvm KVM: PPC: Book3S HV P9: Remove subcore HMI handling 2021-11-24 21:09:03 +11:00
lib Revert "powerpc/code-patching: Improve verification of patchability" 2021-11-29 17:41:52 +11:00
math-emu powerpc/64s: avoid reloading (H)SRR registers if they are still valid 2021-06-25 00:06:55 +10:00
mm powerpc/mm: Move tlbcam_sz() and make it static 2021-11-29 22:49:20 +11:00
net bpf ppc32: Access only if addr is kernel address 2021-11-25 11:25:32 +11:00
perf powerpc/64s: Implement PMU override command line option 2021-11-24 21:08:57 +11:00
platforms powerpc/85xx: Make c293_pcie_pic_init() static 2021-11-29 22:49:17 +11:00
purgatory powerpc/kexec: Don't use .machine ppc64 in trampoline_64.S 2021-04-08 21:17:43 +10:00
sysdev powerpc/tsi108: make EXPORT_SYMBOL follow its function immediately 2021-11-25 11:25:32 +11:00
tools powerpc/head_check: Fix shellcheck errors 2021-08-17 22:52:02 +10:00
xmon powerpc/64s: guard optional TIDR SPR with CPU ftr test 2021-11-24 21:08:56 +11:00
Kbuild kbuild: use more subdir- for visiting subdirectories while cleaning 2021-10-24 13:49:46 +09:00
Kconfig powerpc: select CPUMASK_OFFSTACK if NR_CPUS >= 8192 2021-11-29 22:48:32 +11:00
Kconfig.debug powerpc/ptdump: Convert powerpc to GENERIC_PTDUMP 2021-08-25 13:35:48 +10:00
Makefile Kbuild updates for v5.16 2021-11-08 09:15:45 -08:00
Makefile.postlink powerpc: unrel_branch_check.sh: use nm to find symbol value 2020-09-02 11:00:22 +10:00