5.6-stable patches

added patches:
	bpf-support-llvm-objcopy-for-vmlinux-btf.patch

diff --git a/queue-5.6/bpf-support-llvm-objcopy-for-vmlinux-btf.patch b/queue-5.6/bpf-support-llvm-objcopy-for-vmlinux-btf.patch
new file mode 100644 (file)
index 0000000..b84f8e5
--- /dev/null
+++ b/queue-5.6/bpf-support-llvm-objcopy-for-vmlinux-btf.patch
@@ -0,0 +1,213 @@
+From 90ceddcb495008ac8ba7a3dce297841efcd7d584 Mon Sep 17 00:00:00 2001
+From: Fangrui Song <maskray@google.com>
+Date: Wed, 18 Mar 2020 15:27:46 -0700
+Subject: bpf: Support llvm-objcopy for vmlinux BTF
+
+From: Fangrui Song <maskray@google.com>
+
+commit 90ceddcb495008ac8ba7a3dce297841efcd7d584 upstream.
+
+Simplify gen_btf logic to make it work with llvm-objcopy. The existing
+'file format' and 'architecture' parsing logic is brittle and does not
+work with llvm-objcopy/llvm-objdump.
+
+'file format' output of llvm-objdump>=11 will match GNU objdump, but
+'architecture' (bfdarch) may not.
+
+.BTF in .tmp_vmlinux.btf is non-SHF_ALLOC. Add the SHF_ALLOC flag
+because it is part of vmlinux image used for introspection. C code
+can reference the section via linker script defined __start_BTF and
+__stop_BTF. This fixes a small problem that previous .BTF had the
+SHF_WRITE flag (objcopy -I binary -O elf* synthesized .data).
+
+Additionally, `objcopy -I binary` synthesized symbols
+_binary__btf_vmlinux_bin_start and _binary__btf_vmlinux_bin_stop (not
+used elsewhere) are replaced with more commonplace __start_BTF and
+__stop_BTF.
+
+Add 2>/dev/null because GNU objcopy (but not llvm-objcopy) warns
+"empty loadable segment detected at vaddr=0xffffffff81000000, is this intentional?"
+
+We use a dd command to change the e_type field in the ELF header from
+ET_EXEC to ET_REL so that lld will accept .btf.vmlinux.bin.o.  Accepting
+ET_EXEC as an input file is an extremely rare GNU ld feature that lld
+does not intend to support, because this is error-prone.
+
+The output section description .BTF in include/asm-generic/vmlinux.lds.h
+avoids potential subtle orphan section placement issues and suppresses
+--orphan-handling=warn warnings.
+
+Fixes: df786c9b9476 ("bpf: Force .BTF section start to zero when dumping from vmlinux")
+Fixes: cb0cc635c7a9 ("powerpc: Include .BTF section")
+Reported-by: Nathan Chancellor <natechancellor@gmail.com>
+Signed-off-by: Fangrui Song <maskray@google.com>
+Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
+Tested-by: Stanislav Fomichev <sdf@google.com>
+Tested-by: Andrii Nakryiko <andriin@fb.com>
+Reviewed-by: Stanislav Fomichev <sdf@google.com>
+Reviewed-by: Kees Cook <keescook@chromium.org>
+Acked-by: Andrii Nakryiko <andriin@fb.com>
+Acked-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc)
+Link: https://github.com/ClangBuiltLinux/linux/issues/871
+Link: https://lore.kernel.org/bpf/20200318222746.173648-1-maskray@google.com
+Signed-off-by: Maria Teguiani <teguiani@google.com>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+
+---
+ arch/powerpc/kernel/vmlinux.lds.S |    6 ------
+ include/asm-generic/vmlinux.lds.h |   15 +++++++++++++++
+ kernel/bpf/btf.c                  |    9 ++++-----
+ kernel/bpf/sysfs_btf.c            |   11 +++++------
+ scripts/link-vmlinux.sh           |   24 ++++++++++--------------
+ 5 files changed, 34 insertions(+), 31 deletions(-)
+
+--- a/arch/powerpc/kernel/vmlinux.lds.S
++++ b/arch/powerpc/kernel/vmlinux.lds.S
+@@ -303,12 +303,6 @@ SECTIONS
+               *(.branch_lt)
+       }
+ 
+-#ifdef CONFIG_DEBUG_INFO_BTF
+-      .BTF : AT(ADDR(.BTF) - LOAD_OFFSET) {
+-              *(.BTF)
+-      }
+-#endif
+-
+       .opd : AT(ADDR(.opd) - LOAD_OFFSET) {
+               __start_opd = .;
+               KEEP(*(.opd))
+--- a/include/asm-generic/vmlinux.lds.h
++++ b/include/asm-generic/vmlinux.lds.h
+@@ -535,6 +535,7 @@
+                                                                       \
+       RO_EXCEPTION_TABLE                                              \
+       NOTES                                                           \
++      BTF                                                             \
+                                                                       \
+       . = ALIGN((align));                                             \
+       __end_rodata = .;
+@@ -622,6 +623,20 @@
+       }
+ 
+ /*
++ * .BTF
++ */
++#ifdef CONFIG_DEBUG_INFO_BTF
++#define BTF                                                           \
++      .BTF : AT(ADDR(.BTF) - LOAD_OFFSET) {                           \
++              __start_BTF = .;                                        \
++              *(.BTF)                                                 \
++              __stop_BTF = .;                                         \
++      }
++#else
++#define BTF
++#endif
++
++/*
+  * Init task
+  */
+ #define INIT_TASK_DATA_SECTION(align)                                 \
+--- a/kernel/bpf/btf.c
++++ b/kernel/bpf/btf.c
+@@ -3477,8 +3477,8 @@ errout:
+       return ERR_PTR(err);
+ }
+ 
+-extern char __weak _binary__btf_vmlinux_bin_start[];
+-extern char __weak _binary__btf_vmlinux_bin_end[];
++extern char __weak __start_BTF[];
++extern char __weak __stop_BTF[];
+ extern struct btf *btf_vmlinux;
+ 
+ #define BPF_MAP_TYPE(_id, _ops)
+@@ -3605,9 +3605,8 @@ struct btf *btf_parse_vmlinux(void)
+       }
+       env->btf = btf;
+ 
+-      btf->data = _binary__btf_vmlinux_bin_start;
+-      btf->data_size = _binary__btf_vmlinux_bin_end -
+-              _binary__btf_vmlinux_bin_start;
++      btf->data = __start_BTF;
++      btf->data_size = __stop_BTF - __start_BTF;
+ 
+       err = btf_parse_hdr(env);
+       if (err)
+--- a/kernel/bpf/sysfs_btf.c
++++ b/kernel/bpf/sysfs_btf.c
+@@ -9,15 +9,15 @@
+ #include <linux/sysfs.h>
+ 
+ /* See scripts/link-vmlinux.sh, gen_btf() func for details */
+-extern char __weak _binary__btf_vmlinux_bin_start[];
+-extern char __weak _binary__btf_vmlinux_bin_end[];
++extern char __weak __start_BTF[];
++extern char __weak __stop_BTF[];
+ 
+ static ssize_t
+ btf_vmlinux_read(struct file *file, struct kobject *kobj,
+                struct bin_attribute *bin_attr,
+                char *buf, loff_t off, size_t len)
+ {
+-      memcpy(buf, _binary__btf_vmlinux_bin_start + off, len);
++      memcpy(buf, __start_BTF + off, len);
+       return len;
+ }
+ 
+@@ -30,15 +30,14 @@ static struct kobject *btf_kobj;
+ 
+ static int __init btf_vmlinux_init(void)
+ {
+-      if (!_binary__btf_vmlinux_bin_start)
++      if (!__start_BTF)
+               return 0;
+ 
+       btf_kobj = kobject_create_and_add("btf", kernel_kobj);
+       if (!btf_kobj)
+               return -ENOMEM;
+ 
+-      bin_attr_btf_vmlinux.size = _binary__btf_vmlinux_bin_end -
+-                                  _binary__btf_vmlinux_bin_start;
++      bin_attr_btf_vmlinux.size = __stop_BTF - __start_BTF;
+ 
+       return sysfs_create_bin_file(btf_kobj, &bin_attr_btf_vmlinux);
+ }
+--- a/scripts/link-vmlinux.sh
++++ b/scripts/link-vmlinux.sh
+@@ -113,9 +113,6 @@ vmlinux_link()
+ gen_btf()
+ {
+       local pahole_ver
+-      local bin_arch
+-      local bin_format
+-      local bin_file
+ 
+       if ! [ -x "$(command -v ${PAHOLE})" ]; then
+               echo >&2 "BTF: ${1}: pahole (${PAHOLE}) is not available"
+@@ -133,17 +130,16 @@ gen_btf()
+       info "BTF" ${2}
+       LLVM_OBJCOPY=${OBJCOPY} ${PAHOLE} -J ${1}
+ 
+-      # dump .BTF section into raw binary file to link with final vmlinux
+-      bin_arch=$(LANG=C ${OBJDUMP} -f ${1} | grep architecture | \
+-              cut -d, -f1 | cut -d' ' -f2)
+-      bin_format=$(LANG=C ${OBJDUMP} -f ${1} | grep 'file format' | \
+-              awk '{print $4}')
+-      bin_file=.btf.vmlinux.bin
+-      ${OBJCOPY} --change-section-address .BTF=0 \
+-              --set-section-flags .BTF=alloc -O binary \
+-              --only-section=.BTF ${1} $bin_file
+-      ${OBJCOPY} -I binary -O ${bin_format} -B ${bin_arch} \
+-              --rename-section .data=.BTF $bin_file ${2}
++      # Create ${2} which contains just .BTF section but no symbols. Add
++      # SHF_ALLOC because .BTF will be part of the vmlinux image. --strip-all
++      # deletes all symbols including __start_BTF and __stop_BTF, which will
++      # be redefined in the linker script. Add 2>/dev/null to suppress GNU
++      # objcopy warnings: "empty loadable segment detected at ..."
++      ${OBJCOPY} --only-section=.BTF --set-section-flags .BTF=alloc,readonly \
++              --strip-all ${1} ${2} 2>/dev/null
++      # Change e_type to ET_REL so that it can be used to link final vmlinux.
++      # Unlike GNU ld, lld does not allow an ET_EXEC input.
++      printf '\1' | dd of=${2} conv=notrunc bs=1 seek=16 status=none
+ }
+ 
+ # Create ${2} .o file with all symbols from the ${1} object file

diff --git a/queue-5.6/series b/queue-5.6/series
index 151a30ccf884af21ab8a861480c34cfa675aa47b..d8160a7de0a33ea5f2a224077231c4e387e1bbb1 100644 (file)
--- a/queue-5.6/series
+++ b/queue-5.6/series
@@ -9,3 +9,4 @@ net-ena-xdp-update-napi-budget-for-drop-and-aborted.patch
 genetlink-fix-memory-leaks-in-genl_family_rcv_msg_dumpit.patch
 net-dsa-qca8k-fix-unexpected-gfp-kernel-exception.patch
 tipc-fix-null-pointer-dereference-in-streaming.patch
+bpf-support-llvm-objcopy-for-vmlinux-btf.patch