linux/include/asm-generic/vmlinux.lds.h, branch v4.19

vmlinux.lds.h: Fix linker warnings about orphan .LPBX sections

2018-10-11T21:55:29Z

Enabling both CONFIG_LD_DEAD_CODE_DATA_ELIMINATION=y and CONFIG_GCOV_PROFILE_ALL=y results in linker warnings: warning: orphan section `.data..LPBX1' being placed in section `.data..LPBX1'. LD_DEAD_CODE_DATA_ELIMINATION adds compiler flag -fdata-sections. This option causes GCC to create separate data sections for data objects, including those generated by GCC internally for gcov profiling. The names of these objects start with a dot (.LPBX0, .LPBX1), resulting in section names starting with 'data..'. As section names starting with 'data..' are used for specific purposes in the Linux kernel, the linker script does not automatically include them in the output data section, resulting in the "orphan section" linker warnings. Fix this by specifically including sections named "data..LPBX*" in the data section. Reported-by: Stephen Rothwell Tested-by: Stephen Rothwell Tested-by: Arnd Bergmann Acked-by: Arnd Bergmann Signed-off-by: Peter Oberparleiter Signed-off-by: Stephen Rothwell

vmlinux.lds.h: Fix incomplete .text.exit discards

2018-10-11T21:54:58Z

Enabling CONFIG_GCOV_PROFILE_ALL=y causes linker errors on ARM: `.text.exit' referenced in section `.ARM.exidx.text.exit': defined in discarded section `.text.exit' `.text.exit' referenced in section `.fini_array.00100': defined in discarded section `.text.exit' And related errors on NDS32: `.text.exit' referenced in section `.dtors.65435': defined in discarded section `.text.exit' The gcov compiler flags cause certain compiler versions to generate additional destructor-related sections that are not yet handled by the linker script, resulting in references between discarded and non-discarded sections. Since destructors are not used in the Linux kernel, fix this by discarding these additional sections. Reported-by: Arnd Bergmann Tested-by: Arnd Bergmann Acked-by: Arnd Bergmann Reported-by: Greentime Hu Tested-by: Masami Hiramatsu Signed-off-by: Peter Oberparleiter Signed-off-by: Stephen Rothwell

vmlinux.lds.h: remove stale include

2018-08-22T14:21:44Z

This is unneeded since commit a62143850053 ("vmlinux.lds.h: remove no-op macro VMLINUX_SYMBOL()"). Signed-off-by: Masahiro Yamada

iommu: Remove IOMMU_OF_DECLARE

2018-07-10T15:22:35Z

Now that we use the driver core to stop deferred probe for missing drivers, IOMMU_OF_DECLARE can be removed. This is slightly less optimal than having a list of built-in drivers in that we'll now defer probe twice before giving up. This shouldn't have a significant impact on boot times as past discussions about deferred probe have given no evidence of deferred probe having a substantial impact. Cc: Robin Murphy Cc: Kukjin Kim Cc: Krzysztof Kozlowski Cc: Rob Clark Cc: Heiko Stuebner Cc: Frank Rowand Cc: linux-arm-kernel@lists.infradead.org Cc: iommu@lists.linux-foundation.org Cc: linux-samsung-soc@vger.kernel.org Cc: linux-arm-msm@vger.kernel.org Cc: linux-rockchip@lists.infradead.org Cc: devicetree@vger.kernel.org Acked-by: Will Deacon Acked-by: Marek Szyprowski Acked-by: Joerg Roedel Signed-off-by: Rob Herring Signed-off-by: Greg Kroah-Hartman

kbuild: Fix asm-generic/vmlinux.lds.h for LD_DEAD_CODE_DATA_ELIMINATION

2018-05-17T13:45:00Z

KEEP more tables, and add the function/data section wildcard to more section selections. This is a little ad-hoc at the moment, but kernel code should be moved to consistently use .text..x (note: double dots) for explicit sections and all references to it in the linker script can be made with TEXT_MAIN, and similarly for other sections. For now, let's see if major architectures move to enabling this option then we can do some refactoring passes. Otherwise if it remains unused or superseded by LTO, this may not be required. Signed-off-by: Nicholas Piggin Signed-off-by: Masahiro Yamada

vmlinux.lds.h: remove no-op macro VMLINUX_SYMBOL()

2018-05-17T13:44:58Z

Now that VMLINUX_SYMBOL() is no-op, clean up the linker script. Signed-off-by: Masahiro Yamada Reviewed-by: Sam Ravnborg

earlycon: Use a pointer table to fix __earlycon_table stride

2018-04-23T08:06:59Z

Commit 99492c39f39f ("earlycon: Fix __earlycon_table stride") tried to fix __earlycon_table stride by forcing the earlycon_id struct alignment to 32 and asking the linker to 32-byte align the __earlycon_table symbol. This fix was based on commit 07fca0e57fca92 ("tracing: Properly align linker defined symbols") which tried a similar fix for the tracing subsystem. However, this fix doesn't quite work because there is no guarantee that gcc will place structures packed into an array format. In fact, gcc 4.9 chooses to 64-byte align these structs by inserting additional padding between the entries because it has no clue that they are supposed to be in an array. If we are unlucky, the linker will assign symbol "__earlycon_table" to a 32-byte aligned address which does not correspond to the 64-byte aligned contents of section "__earlycon_table". To address this same problem, the fix to the tracing system was subsequently re-implemented using a more robust table of pointers approach by commits: 3d56e331b653 ("tracing: Replace syscall_meta_data struct array with pointer array") 654986462939 ("tracepoints: Fix section alignment using pointer array") e4a9ea5ee7c8 ("tracing: Replace trace_event struct array with pointer array") Let's use this same "array of pointers to structs" approach for EARLYCON_TABLE. Fixes: 99492c39f39f ("earlycon: Fix __earlycon_table stride") Signed-off-by: Daniel Kurtz Suggested-by: Aaron Durbin Reviewed-by: Rob Herring Tested-by: Guenter Roeck Reviewed-by: Guenter Roeck Cc: stable Signed-off-by: Greg Kroah-Hartman

Merge tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux

2018-04-04T23:01:43Z

Pull arm64 updates from Will Deacon: "Nothing particularly stands out here, probably because people were tied up with spectre/meltdown stuff last time around. Still, the main pieces are: - Rework of our CPU features framework so that we can whitelist CPUs that don't require kpti even in a heterogeneous system - Support for the IDC/DIC architecture extensions, which allow us to elide instruction and data cache maintenance when writing out instructions - Removal of the large memory model which resulted in suboptimal codegen by the compiler and increased the use of literal pools, which could potentially be used as ROP gadgets since they are mapped as executable - Rework of forced signal delivery so that the siginfo_t is well-formed and handling of show_unhandled_signals is consolidated and made consistent between different fault types - More siginfo cleanup based on the initial patches from Eric Biederman - Workaround for Cortex-A55 erratum #1024718 - Some small ACPI IORT updates and cleanups from Lorenzo Pieralisi - Misc cleanups and non-critical fixes" * tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux: (70 commits) arm64: uaccess: Fix omissions from usercopy whitelist arm64: fpsimd: Split cpu field out from struct fpsimd_state arm64: tlbflush: avoid writing RES0 bits arm64: cmpxchg: Include linux/compiler.h in asm/cmpxchg.h arm64: move percpu cmpxchg implementation from cmpxchg.h to percpu.h arm64: cmpxchg: Include build_bug.h instead of bug.h for BUILD_BUG arm64: lse: Include compiler_types.h and export.h for out-of-line LL/SC arm64: fpsimd: include in fpsimd.h drivers/perf: arm_pmu_platform: do not warn about affinity on uniprocessor perf: arm_spe: include linux/vmalloc.h for vmap() Revert "arm64: Revert L1_CACHE_SHIFT back to 6 (64-byte cache line size)" arm64: cpufeature: Avoid warnings due to unused symbols arm64: Add work around for Arm Cortex-A55 Erratum 1024718 arm64: Delay enabling hardware DBM feature arm64: Add MIDR encoding for Arm Cortex-A55 and Cortex-A35 arm64: capabilities: Handle shared entries arm64: capabilities: Add support for checks based on a list of MIDRs arm64: Add helpers for checking CPU MIDR against a range arm64: capabilities: Clean up midr range helpers arm64: capabilities: Change scope of VHE to Boot CPU feature ...

bpf: introduce BPF_RAW_TRACEPOINT

2018-03-28T20:55:19Z

Introduce BPF_PROG_TYPE_RAW_TRACEPOINT bpf program type to access kernel internal arguments of the tracepoints in their raw form. >From bpf program point of view the access to the arguments look like: struct bpf_raw_tracepoint_args { __u64 args[0]; }; int bpf_prog(struct bpf_raw_tracepoint_args *ctx) { // program can read args[N] where N depends on tracepoint // and statically verified at program load+attach time } kprobe+bpf infrastructure allows programs access function arguments. This feature allows programs access raw tracepoint arguments. Similar to proposed 'dynamic ftrace events' there are no abi guarantees to what the tracepoints arguments are and what their meaning is. The program needs to type cast args properly and use bpf_probe_read() helper to access struct fields when argument is a pointer. For every tracepoint __bpf_trace_##call function is prepared. In assembler it looks like: (gdb) disassemble __bpf_trace_xdp_exception Dump of assembler code for function __bpf_trace_xdp_exception: 0xffffffff81132080 <+0>: mov %ecx,%ecx 0xffffffff81132082 <+2>: jmpq 0xffffffff811231f0 where TRACE_EVENT(xdp_exception, TP_PROTO(const struct net_device *dev, const struct bpf_prog *xdp, u32 act), The above assembler snippet is casting 32-bit 'act' field into 'u64' to pass into bpf_trace_run3(), while 'dev' and 'xdp' args are passed as-is. All of ~500 of __bpf_trace_*() functions are only 5-10 byte long and in total this approach adds 7k bytes to .text. This approach gives the lowest possible overhead while calling trace_xdp_exception() from kernel C code and transitioning into bpf land. Since tracepoint+bpf are used at speeds of 1M+ events per second this is valuable optimization. The new BPF_RAW_TRACEPOINT_OPEN sys_bpf command is introduced that returns anon_inode FD of 'bpf-raw-tracepoint' object. The user space looks like: // load bpf prog with BPF_PROG_TYPE_RAW_TRACEPOINT type prog_fd = bpf_prog_load(...); // receive anon_inode fd for given bpf_raw_tracepoint with prog attached raw_tp_fd = bpf_raw_tracepoint_open("xdp_exception", prog_fd); Ctrl-C of tracing daemon or cmdline tool that uses this feature will automatically detach bpf program, unload it and unregister tracepoint probe. On the kernel side the __bpf_raw_tp_map section of pointers to tracepoint definition and to __bpf_trace_*() probe function is used to find a tracepoint with "xdp_exception" name and corresponding __bpf_trace_xdp_exception() probe function which are passed to tracepoint_probe_register() to connect probe with tracepoint. Addition of bpf_raw_tracepoint doesn't interfere with ftrace and perf tracepoint mechanisms. perf_event_open() can be used in parallel on the same tracepoint. Multiple bpf_raw_tracepoint_open("xdp_exception", prog_fd) are permitted. Each with its own bpf program. The kernel will execute all tracepoint probes and all attached bpf programs. In the future bpf_raw_tracepoints can be extended with query/introspection logic. __bpf_raw_tp_map section logic was contributed by Steven Rostedt Signed-off-by: Alexei Starovoitov Signed-off-by: Steven Rostedt (VMware) Acked-by: Steven Rostedt (VMware) Signed-off-by: Daniel Borkmann

ACPI/IORT: Remove linker section for IORT entries again

2018-03-08T11:22:15Z

In commit 316ca8804ea8 ("ACPI/IORT: Remove linker section for IORT entries probing"), iort entries was removed in vmlinux.lds.h. But in commit 2fcc112af37f ("clocksource/drivers: Rename clksrc table to timer"), this line was back incorrectly. It does no harm except for adding some useless symbols, so fix it. Signed-off-by: Jia He Signed-off-by: Lorenzo Pieralisi Acked-by: Daniel Lezcano