Hi Ard, On Wed, Jan 11, 2023 at 11:22:32AM +0100, Ard Biesheuvel wrote: > Reorganize the ID map slightly so that only code that is executed with > the MMU off or via the 1:1 mapping remains. This allows us to move the > identity map out of the .text segment, as it will no longer need > executable permissions via the kernel mapping. > > Signed-off-by: Ard Biesheuvel <ardb@xxxxxxxxxx> > --- > arch/arm64/kernel/head.S | 28 +++++++++++--------- > arch/arm64/kernel/vmlinux.lds.S | 2 +- > arch/arm64/mm/proc.S | 2 -- > 3 files changed, 16 insertions(+), 16 deletions(-) > > diff --git a/arch/arm64/kernel/head.S b/arch/arm64/kernel/head.S > index c4e12d466a5f35f0..bec97aad092c2b43 100644 > --- a/arch/arm64/kernel/head.S > +++ b/arch/arm64/kernel/head.S > @@ -543,19 +543,6 @@ SYM_INNER_LABEL(init_el2, SYM_L_LOCAL) > eret > SYM_FUNC_END(init_kernel_el) > > -/* > - * Sets the __boot_cpu_mode flag depending on the CPU boot mode passed > - * in w0. See arch/arm64/include/asm/virt.h for more info. > - */ > -SYM_FUNC_START_LOCAL(set_cpu_boot_mode_flag) > - adr_l x1, __boot_cpu_mode > - cmp w0, #BOOT_CPU_MODE_EL2 > - b.ne 1f > - add x1, x1, #4 > -1: str w0, [x1] // Save CPU boot mode > - ret > -SYM_FUNC_END(set_cpu_boot_mode_flag) > - > /* > * This provides a "holding pen" for platforms to hold all secondary > * cores are held until we're ready for them to initialise. > @@ -599,6 +586,7 @@ SYM_FUNC_START_LOCAL(secondary_startup) > br x8 > SYM_FUNC_END(secondary_startup) > > + .text > SYM_FUNC_START_LOCAL(__secondary_switched) > mov x0, x20 > bl set_cpu_boot_mode_flag > @@ -631,6 +619,19 @@ SYM_FUNC_START_LOCAL(__secondary_too_slow) > b __secondary_too_slow > SYM_FUNC_END(__secondary_too_slow) > > +/* > + * Sets the __boot_cpu_mode flag depending on the CPU boot mode passed > + * in w0. See arch/arm64/include/asm/virt.h for more info. > + */ > +SYM_FUNC_START_LOCAL(set_cpu_boot_mode_flag) > + adr_l x1, __boot_cpu_mode > + cmp w0, #BOOT_CPU_MODE_EL2 > + b.ne 1f > + add x1, x1, #4 > +1: str w0, [x1] // Save CPU boot mode > + ret > +SYM_FUNC_END(set_cpu_boot_mode_flag) > + > /* > * The booting CPU updates the failed status @__early_cpu_boot_status, > * with MMU turned off. > @@ -662,6 +663,7 @@ SYM_FUNC_END(__secondary_too_slow) > * Checks if the selected granule size is supported by the CPU. > * If it isn't, park the CPU > */ > + .section ".idmap.text","awx" > SYM_FUNC_START(__enable_mmu) > mrs x3, ID_AA64MMFR0_EL1 > ubfx x3, x3, #ID_AA64MMFR0_EL1_TGRAN_SHIFT, 4 > diff --git a/arch/arm64/kernel/vmlinux.lds.S b/arch/arm64/kernel/vmlinux.lds.S > index 4c13dafc98b8400f..407415a5163ab62f 100644 > --- a/arch/arm64/kernel/vmlinux.lds.S > +++ b/arch/arm64/kernel/vmlinux.lds.S > @@ -179,7 +179,6 @@ SECTIONS > LOCK_TEXT > KPROBES_TEXT > HYPERVISOR_TEXT > - IDMAP_TEXT > *(.gnu.warning) > . = ALIGN(16); > *(.got) /* Global offset table */ > @@ -206,6 +205,7 @@ SECTIONS > TRAMP_TEXT > HIBERNATE_TEXT > KEXEC_TEXT > + IDMAP_TEXT > . = ALIGN(PAGE_SIZE); > } > > diff --git a/arch/arm64/mm/proc.S b/arch/arm64/mm/proc.S > index 066fa60b93d24827..91410f48809000a0 100644 > --- a/arch/arm64/mm/proc.S > +++ b/arch/arm64/mm/proc.S > @@ -110,7 +110,6 @@ SYM_FUNC_END(cpu_do_suspend) > * > * x0: Address of context pointer > */ > - .pushsection ".idmap.text", "awx" > SYM_FUNC_START(cpu_do_resume) > ldp x2, x3, [x0] > ldp x4, x5, [x0, #16] > @@ -166,7 +165,6 @@ alternative_else_nop_endif > isb > ret > SYM_FUNC_END(cpu_do_resume) > - .popsection > #endif > > .pushsection ".idmap.text", "awx" > -- > 2.39.0 > Sorry you have to keep hearing from me, I am starting to feel like a nuisance :) apologies if this is already been reported, I did a search of lore and did not find anything. I have noticed the following message on my arm64 machines recently and I had some time to bisect it down to this change in -next (log below): [ 0.029481] kprobes: Failed to populate blacklist (error -22), kprobes not restricted, be careful using them! I can trivially reproduce it with defconfig + CONFIG_KPROBES=y in QEMU. If there is any other information I can provide or patches I can test, I am more than happy to do so. Cheers, Nathan # bad: [ea4dabbb4ad7eb52632a2ca0b8f89f0ea7c55dcf] Add linux-next specific files for 20230202 # good: [9f266ccaa2f5228bfe67ad58a94ca4e0109b954a] Merge tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost git bisect start 'ea4dabbb4ad7eb52632a2ca0b8f89f0ea7c55dcf' '9f266ccaa2f5228bfe67ad58a94ca4e0109b954a' # bad: [1212e8a2ede5d43ffa423f6bb15dc128bc442c17] Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/cryptodev-2.6.git git bisect bad 1212e8a2ede5d43ffa423f6bb15dc128bc442c17 # bad: [61a09f7913443728509eaba2b10566372e39f4fc] Merge branch 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/idmapping.git git bisect bad 61a09f7913443728509eaba2b10566372e39f4fc # good: [642eb331c5eddadf2a9b0ea171c0605788627dae] soc: document merges git bisect good 642eb331c5eddadf2a9b0ea171c0605788627dae # bad: [8c08bee280c147d47db13297c5f4d11fdc915fec] Merge branch 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/tmlind/linux-omap.git git bisect bad 8c08bee280c147d47db13297c5f4d11fdc915fec # good: [ab0a5c9e8c2649f43e6d49b65785189e208df506] Merge branch 'perf/core' of git://git.kernel.org/pub/scm/linux/kernel/git/acme/linux.git git bisect good ab0a5c9e8c2649f43e6d49b65785189e208df506 # bad: [706652c32b3d2a55b52f1e33ee1d2f98a0eafed0] Merge branch 'asahi-soc/for-next' of https://github.com/AsahiLinux/linux.git git bisect bad 706652c32b3d2a55b52f1e33ee1d2f98a0eafed0 # bad: [13c0a41d2cb2265661c7178cbe986592c906ef0b] Merge branches 'for-next/sysreg', 'for-next/sme', 'for-next/kselftest', 'for-next/misc', 'for-next/sme2', 'for-next/tpidr2', 'for-next/scs', 'for-next/compat-hwcap', 'for-next/ftrace', 'for-next/efi-boot-mmu-on', 'for-next/ptrauth' and 'for-next/pseudo-nmi' into for-next/core git bisect bad 13c0a41d2cb2265661c7178cbe986592c906ef0b # good: [b2ab432bcf65e6fa3ec3fef6dd08796404b009d0] kselftest/arm64: Remove redundant _start labels from zt-test git bisect good b2ab432bcf65e6fa3ec3fef6dd08796404b009d0 # good: [a7db82f18cd3d85ea8ef70fca5946b441187ed6d] kselftest/arm64: Fix enumeration of systems without 128 bit SME for SSVE+ZA git bisect good a7db82f18cd3d85ea8ef70fca5946b441187ed6d # good: [dc4824faa265db1bc93449e8ec386a0245404fa6] arm64: avoid executing padding bytes during kexec / hibernation git bisect good dc4824faa265db1bc93449e8ec386a0245404fa6 # good: [004fc58f917cfea5d7190139e3ed1b7a13e39c25] arm64/mm: Intercept pfn changes in set_pte_at() git bisect good 004fc58f917cfea5d7190139e3ed1b7a13e39c25 # good: [4f2c9bf16a4bc209a674e7b76d8e829b917c7f84] arm64: Add compat hwcap SSBS git bisect good 4f2c9bf16a4bc209a674e7b76d8e829b917c7f84 # bad: [2ced0f30a426c7301350681f838344d5aea711e3] arm64: head: Switch endianness before populating the ID map git bisect bad 2ced0f30a426c7301350681f838344d5aea711e3 # bad: [9d7c13e5dde31270eb48a34204a2e06b1a719546] arm64: head: record the MMU state at primary entry git bisect bad 9d7c13e5dde31270eb48a34204a2e06b1a719546 # bad: [af7249b317e4d0b3d5a0ebbb7ee7a0f336ca7bca] arm64: kernel: move identity map out of .text mapping git bisect bad af7249b317e4d0b3d5a0ebbb7ee7a0f336ca7bca # good: [82e4958800c01daa7662362ee9543065bd14c852] arm64: head: Move all finalise_el2 calls to after __enable_mmu git bisect good 82e4958800c01daa7662362ee9543065bd14c852 # first bad commit: [af7249b317e4d0b3d5a0ebbb7ee7a0f336ca7bca] arm64: kernel: move identity map out of .text mapping
