linux-stable/arch/powerpc/kernel/vmlinux.lds.S
Naveen N Rao ea73179e64 powerpc/ftrace: Ignore ftrace locations in exit text sections
Michael reported that we are seeing an ftrace bug on bootup when KASAN
is enabled and we are using -fpatchable-function-entry:

  ftrace: allocating 47780 entries in 18 pages
  ftrace-powerpc: 0xc0000000020b3d5c: No module provided for non-kernel address
  ------------[ ftrace bug ]------------
  ftrace faulted on modifying
  [<c0000000020b3d5c>] 0xc0000000020b3d5c
  Initializing ftrace call sites
  ftrace record flags: 0
   (0)
   expected tramp: c00000000008cef4
  ------------[ cut here ]------------
  WARNING: CPU: 0 PID: 0 at kernel/trace/ftrace.c:2180 ftrace_bug+0x3c0/0x424
  Modules linked in:
  CPU: 0 PID: 0 Comm: swapper Not tainted 6.5.0-rc3-00120-g0f71dcfb4aef #860
  Hardware name: IBM pSeries (emulated by qemu) POWER9 (raw) 0x4e1202 0xf000005 of:SLOF,HEAD hv:linux,kvm pSeries
  NIP:  c0000000003aa81c LR: c0000000003aa818 CTR: 0000000000000000
  REGS: c0000000033cfab0 TRAP: 0700   Not tainted  (6.5.0-rc3-00120-g0f71dcfb4aef)
  MSR:  8000000002021033 <SF,VEC,ME,IR,DR,RI,LE>  CR: 28028240  XER: 00000000
  CFAR: c0000000002781a8 IRQMASK: 3
  ...
  NIP [c0000000003aa81c] ftrace_bug+0x3c0/0x424
  LR [c0000000003aa818] ftrace_bug+0x3bc/0x424
  Call Trace:
   ftrace_bug+0x3bc/0x424 (unreliable)
   ftrace_process_locs+0x5f4/0x8a0
   ftrace_init+0xc0/0x1d0
   start_kernel+0x1d8/0x484

With CONFIG_FTRACE_MCOUNT_USE_PATCHABLE_FUNCTION_ENTRY=y and
CONFIG_KASAN=y, compiler emits nops in functions that it generates for
registering and unregistering global variables (unlike with -pg and
-mprofile-kernel where calls to _mcount() are not generated in those
functions). Those functions then end up in INIT_TEXT and EXIT_TEXT
respectively. We don't expect to see any profiled functions in
EXIT_TEXT, so ftrace_init_nop() assumes that all addresses that aren't
in the core kernel text belongs to a module. Since these functions do
not match that criteria, we see the above bug.

Address this by having ftrace ignore all locations in the text exit
sections of vmlinux.

Fixes: 0f71dcfb4a ("powerpc/ftrace: Add support for -fpatchable-function-entry")
Cc: stable@vger.kernel.org # v6.6+
Reported-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Naveen N Rao <naveen@kernel.org>
Reviewed-by: Benjamin Gray <bgray@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20240213175410.1091313-1-naveen@kernel.org
2024-02-14 14:24:06 +11:00

426 lines
9.2 KiB
ArmAsm

/* SPDX-License-Identifier: GPL-2.0 */
#ifdef CONFIG_PPC64
#define PROVIDE32(x) PROVIDE(__unused__##x)
#else
#define PROVIDE32(x) PROVIDE(x)
#endif
#define BSS_FIRST_SECTIONS *(.bss.prominit)
#define EMITS_PT_NOTE
#define RO_EXCEPTION_TABLE_ALIGN 0
#define RUNTIME_DISCARD_EXIT
#define SOFT_MASK_TABLE(align) \
. = ALIGN(align); \
__soft_mask_table : AT(ADDR(__soft_mask_table) - LOAD_OFFSET) { \
__start___soft_mask_table = .; \
KEEP(*(__soft_mask_table)) \
__stop___soft_mask_table = .; \
}
#define RESTART_TABLE(align) \
. = ALIGN(align); \
__restart_table : AT(ADDR(__restart_table) - LOAD_OFFSET) { \
__start___restart_table = .; \
KEEP(*(__restart_table)) \
__stop___restart_table = .; \
}
#include <asm/page.h>
#include <asm-generic/vmlinux.lds.h>
#include <asm/cache.h>
#include <asm/thread_info.h>
#define STRICT_ALIGN_SIZE (1 << CONFIG_DATA_SHIFT)
#if STRICT_ALIGN_SIZE < PAGE_SIZE
#error "CONFIG_DATA_SHIFT must be >= PAGE_SHIFT"
#endif
ENTRY(_stext)
PHDRS {
text PT_LOAD FLAGS(7); /* RWX */
note PT_NOTE FLAGS(0);
}
#ifdef CONFIG_PPC64
OUTPUT_ARCH(powerpc:common64)
jiffies = jiffies_64;
#else
OUTPUT_ARCH(powerpc:common)
jiffies = jiffies_64 + 4;
#endif
SECTIONS
{
. = KERNELBASE;
/*
* Text, read only data and other permanent read-only sections
*/
_text = .;
_stext = .;
/*
* Head text.
* This needs to be in its own output section to avoid ld placing
* branch trampoline stubs randomly throughout the fixed sections,
* which it will do (even if the branch comes from another section)
* in order to optimize stub generation.
*/
.head.text : AT(ADDR(.head.text) - LOAD_OFFSET) {
#ifdef CONFIG_PPC64
KEEP(*(.head.text.first_256B));
#ifdef CONFIG_PPC_BOOK3E_64
#else
KEEP(*(.head.text.real_vectors));
*(.head.text.real_trampolines);
KEEP(*(.head.text.virt_vectors));
*(.head.text.virt_trampolines);
# if defined(CONFIG_PPC_PSERIES) || defined(CONFIG_PPC_POWERNV)
KEEP(*(.head.data.fwnmi_page));
# endif
#endif
#else /* !CONFIG_PPC64 */
HEAD_TEXT
#endif
} :text
__head_end = .;
#ifdef CONFIG_PPC64
/*
* ALIGN(0) overrides the default output section alignment because
* this needs to start right after .head.text in order for fixed
* section placement to work.
*/
.text ALIGN(0) : AT(ADDR(.text) - LOAD_OFFSET) {
#ifdef CONFIG_LD_HEAD_STUB_CATCH
KEEP(*(.linker_stub_catch));
. = . ;
#endif
#else
.text : AT(ADDR(.text) - LOAD_OFFSET) {
ALIGN_FUNCTION();
#endif
/* careful! __ftr_alt_* sections need to be close to .text */
*(.text.hot .text.hot.* TEXT_MAIN .text.fixup .text.unlikely .text.unlikely.* .fixup __ftr_alt_* .ref.text);
*(.tramp.ftrace.text);
NOINSTR_TEXT
SCHED_TEXT
LOCK_TEXT
KPROBES_TEXT
IRQENTRY_TEXT
SOFTIRQENTRY_TEXT
/*
* -Os builds call FP save/restore functions. The powerpc64
* linker generates those on demand in the .sfpr section.
* .sfpr gets placed at the beginning of a group of input
* sections, which can break start-of-text offset if it is
* included with the main text sections, so put it by itself.
*/
*(.sfpr);
*(.text.asan.* .text.tsan.*)
MEM_KEEP(init.text)
MEM_KEEP(exit.text)
} :text
. = ALIGN(PAGE_SIZE);
_etext = .;
PROVIDE32 (etext = .);
/* Read-only data */
RO_DATA(PAGE_SIZE)
#ifdef CONFIG_PPC32
.sdata2 : AT(ADDR(.sdata2) - LOAD_OFFSET) {
*(.sdata2)
}
#endif
.data.rel.ro : AT(ADDR(.data.rel.ro) - LOAD_OFFSET) {
*(.data.rel.ro .data.rel.ro.*)
}
.branch_lt : AT(ADDR(.branch_lt) - LOAD_OFFSET) {
*(.branch_lt)
}
#ifdef CONFIG_PPC32
.got1 : AT(ADDR(.got1) - LOAD_OFFSET) {
*(.got1)
}
.got2 : AT(ADDR(.got2) - LOAD_OFFSET) {
__got2_start = .;
*(.got2)
__got2_end = .;
}
.got : AT(ADDR(.got) - LOAD_OFFSET) {
*(.got)
*(.got.plt)
}
.plt : AT(ADDR(.plt) - LOAD_OFFSET) {
/* XXX: is .plt (and .got.plt) required? */
*(.plt)
}
#else /* CONFIG_PPC32 */
#ifndef CONFIG_PPC_KERNEL_PCREL
.toc1 : AT(ADDR(.toc1) - LOAD_OFFSET) {
*(.toc1)
}
#endif
.got : AT(ADDR(.got) - LOAD_OFFSET) ALIGN(256) {
#ifdef CONFIG_PPC_KERNEL_PCREL
*(.got)
#else
*(.got .toc)
#endif
}
SOFT_MASK_TABLE(8)
RESTART_TABLE(8)
#ifdef CONFIG_PPC64_ELF_ABI_V1
.opd : AT(ADDR(.opd) - LOAD_OFFSET) {
__start_opd = .;
KEEP(*(.opd))
__end_opd = .;
}
#endif
. = ALIGN(8);
__stf_entry_barrier_fixup : AT(ADDR(__stf_entry_barrier_fixup) - LOAD_OFFSET) {
__start___stf_entry_barrier_fixup = .;
*(__stf_entry_barrier_fixup)
__stop___stf_entry_barrier_fixup = .;
}
. = ALIGN(8);
__uaccess_flush_fixup : AT(ADDR(__uaccess_flush_fixup) - LOAD_OFFSET) {
__start___uaccess_flush_fixup = .;
*(__uaccess_flush_fixup)
__stop___uaccess_flush_fixup = .;
}
. = ALIGN(8);
__entry_flush_fixup : AT(ADDR(__entry_flush_fixup) - LOAD_OFFSET) {
__start___entry_flush_fixup = .;
*(__entry_flush_fixup)
__stop___entry_flush_fixup = .;
}
. = ALIGN(8);
__scv_entry_flush_fixup : AT(ADDR(__scv_entry_flush_fixup) - LOAD_OFFSET) {
__start___scv_entry_flush_fixup = .;
*(__scv_entry_flush_fixup)
__stop___scv_entry_flush_fixup = .;
}
. = ALIGN(8);
__stf_exit_barrier_fixup : AT(ADDR(__stf_exit_barrier_fixup) - LOAD_OFFSET) {
__start___stf_exit_barrier_fixup = .;
*(__stf_exit_barrier_fixup)
__stop___stf_exit_barrier_fixup = .;
}
. = ALIGN(8);
__rfi_flush_fixup : AT(ADDR(__rfi_flush_fixup) - LOAD_OFFSET) {
__start___rfi_flush_fixup = .;
*(__rfi_flush_fixup)
__stop___rfi_flush_fixup = .;
}
#endif /* CONFIG_PPC32 */
#ifdef CONFIG_PPC_BARRIER_NOSPEC
. = ALIGN(8);
__spec_barrier_fixup : AT(ADDR(__spec_barrier_fixup) - LOAD_OFFSET) {
__start___barrier_nospec_fixup = .;
*(__barrier_nospec_fixup)
__stop___barrier_nospec_fixup = .;
}
#endif /* CONFIG_PPC_BARRIER_NOSPEC */
#ifdef CONFIG_PPC_E500
. = ALIGN(8);
__spec_btb_flush_fixup : AT(ADDR(__spec_btb_flush_fixup) - LOAD_OFFSET) {
__start__btb_flush_fixup = .;
*(__btb_flush_fixup)
__stop__btb_flush_fixup = .;
}
#endif
/*
* Various code relies on __init_begin being at the strict RWX boundary.
*/
. = ALIGN(STRICT_ALIGN_SIZE);
__srwx_boundary = .;
__end_rodata = .;
__init_begin = .;
/*
* Init sections discarded at runtime
*/
.init.text : AT(ADDR(.init.text) - LOAD_OFFSET) {
_sinittext = .;
INIT_TEXT
/*
*.init.text might be RO so we must ensure this section ends on
* a page boundary.
*/
. = ALIGN(PAGE_SIZE);
_einittext = .;
*(.tramp.ftrace.init);
} :text
/* .exit.text is discarded at runtime, not link time,
* to deal with references from __bug_table
*/
.exit.text : AT(ADDR(.exit.text) - LOAD_OFFSET) {
__exittext_begin = .;
EXIT_TEXT
__exittext_end = .;
}
. = ALIGN(PAGE_SIZE);
INIT_DATA_SECTION(16)
. = ALIGN(8);
__ftr_fixup : AT(ADDR(__ftr_fixup) - LOAD_OFFSET) {
__start___ftr_fixup = .;
KEEP(*(__ftr_fixup))
__stop___ftr_fixup = .;
}
. = ALIGN(8);
__mmu_ftr_fixup : AT(ADDR(__mmu_ftr_fixup) - LOAD_OFFSET) {
__start___mmu_ftr_fixup = .;
KEEP(*(__mmu_ftr_fixup))
__stop___mmu_ftr_fixup = .;
}
. = ALIGN(8);
__lwsync_fixup : AT(ADDR(__lwsync_fixup) - LOAD_OFFSET) {
__start___lwsync_fixup = .;
KEEP(*(__lwsync_fixup))
__stop___lwsync_fixup = .;
}
#ifdef CONFIG_PPC64
. = ALIGN(8);
__fw_ftr_fixup : AT(ADDR(__fw_ftr_fixup) - LOAD_OFFSET) {
__start___fw_ftr_fixup = .;
KEEP(*(__fw_ftr_fixup))
__stop___fw_ftr_fixup = .;
}
#endif
PERCPU_SECTION(L1_CACHE_BYTES)
. = ALIGN(8);
.machine.desc : AT(ADDR(.machine.desc) - LOAD_OFFSET) {
__machine_desc_start = . ;
KEEP(*(.machine.desc))
__machine_desc_end = . ;
}
#ifdef CONFIG_RELOCATABLE
. = ALIGN(8);
.dynsym : AT(ADDR(.dynsym) - LOAD_OFFSET)
{
__dynamic_symtab = .;
*(.dynsym)
}
.dynstr : AT(ADDR(.dynstr) - LOAD_OFFSET) { *(.dynstr) }
.dynamic : AT(ADDR(.dynamic) - LOAD_OFFSET)
{
__dynamic_start = .;
*(.dynamic)
}
.hash : AT(ADDR(.hash) - LOAD_OFFSET) { *(.hash) }
.gnu.hash : AT(ADDR(.gnu.hash) - LOAD_OFFSET) { *(.gnu.hash) }
.interp : AT(ADDR(.interp) - LOAD_OFFSET) { *(.interp) }
.rela.dyn : AT(ADDR(.rela.dyn) - LOAD_OFFSET)
{
__rela_dyn_start = .;
*(.rela*)
}
#endif
/* .exit.data is discarded at runtime, not link time,
* to deal with references from .exit.text
*/
.exit.data : AT(ADDR(.exit.data) - LOAD_OFFSET) {
EXIT_DATA
}
/* freed after init ends here */
. = ALIGN(PAGE_SIZE);
__init_end = .;
/*
* And now the various read/write data
*/
. = ALIGN(PAGE_SIZE);
_sdata = .;
.data : AT(ADDR(.data) - LOAD_OFFSET) {
DATA_DATA
*(.data.rel*)
#ifdef CONFIG_PPC32
*(SDATA_MAIN)
#endif
}
/* The initial task and kernel stack */
INIT_TASK_DATA_SECTION(THREAD_ALIGN)
.data..page_aligned : AT(ADDR(.data..page_aligned) - LOAD_OFFSET) {
PAGE_ALIGNED_DATA(PAGE_SIZE)
}
.data..cacheline_aligned : AT(ADDR(.data..cacheline_aligned) - LOAD_OFFSET) {
CACHELINE_ALIGNED_DATA(L1_CACHE_BYTES)
}
.data..read_mostly : AT(ADDR(.data..read_mostly) - LOAD_OFFSET) {
READ_MOSTLY_DATA(L1_CACHE_BYTES)
}
. = ALIGN(PAGE_SIZE);
.data_nosave : AT(ADDR(.data_nosave) - LOAD_OFFSET) {
NOSAVE_DATA
}
BUG_TABLE
. = ALIGN(PAGE_SIZE);
_edata = .;
PROVIDE32 (edata = .);
/*
* And finally the bss
*/
BSS_SECTION(0, 0, 0)
. = ALIGN(PAGE_SIZE);
_end = . ;
PROVIDE32 (end = .);
DWARF_DEBUG
ELF_DETAILS
DISCARDS
/DISCARD/ : {
*(*.EMB.apuinfo)
*(.glink .iplt .plt)
*(.gnu.version*)
*(.gnu.attributes)
*(.eh_frame)
#ifndef CONFIG_RELOCATABLE
*(.rela*)
#endif
}
}