File libpulp-0001-Non-ABI-compliant-__tls_get_addr-f... of Package glibc

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File libpulp-0001-Non-ABI-compliant-__tls_get_addr-for-libpulp.patch of Package glibc (Revision fc8500aa4db0245927fcb5c0280c1a37)

Currently displaying revision fc8500aa4db0245927fcb5c0280c1a37 , Show latest

diff -ru glibc-2.26.orig/elf/Versions glibc-2.26/elf/Versions
--- glibc-2.26.orig/elf/Versions	2017-08-02 12:57:16.000000000 +0000
+++ glibc-2.26/elf/Versions	2021-03-11 19:21:00.091940293 +0000
@@ -74,4 +74,9 @@
     # Set value of a tunable.
     __tunable_get_val;
   }
+  GLIBC_LIBPULP1 {
+    # Non ABI-compliant version of __tls_get_addr to avoid the need of
+    # saving/restoring registers on the fast path.
+    __libpulp_tls_get_addr;
+  }
 }
Only in glibc-2.26/elf: Versions.orig
diff -ru glibc-2.26.orig/sysdeps/unix/sysv/linux/x86_64/64/ld.abilist glibc-2.26/sysdeps/unix/sysv/linux/x86_64/64/ld.abilist
--- glibc-2.26.orig/sysdeps/unix/sysv/linux/x86_64/64/ld.abilist	2017-08-02 12:57:16.000000000 +0000
+++ glibc-2.26/sysdeps/unix/sysv/linux/x86_64/64/ld.abilist	2021-03-11 19:21:47.788089264 +0000
@@ -9,3 +9,5 @@
 GLIBC_2.3 GLIBC_2.3 A
 GLIBC_2.3 __tls_get_addr F
 GLIBC_2.4 GLIBC_2.4 A
+GLIBC_LIBPULP1 GLIBC_LIBPULP1 A
+GLIBC_LIBPULP1 __libpulp_tls_get_addr F
Only in glibc-2.26/sysdeps/unix/sysv/linux/x86_64/64: ld.abilist.orig
Only in glibc-2.26/sysdeps/unix/sysv/linux/x86_64/64: ld.abilist.rej
diff -ru glibc-2.26.orig/sysdeps/x86_64/tls_get_addr.S glibc-2.26/sysdeps/x86_64/tls_get_addr.S
--- glibc-2.26.orig/sysdeps/x86_64/tls_get_addr.S	2017-08-02 12:57:16.000000000 +0000
+++ glibc-2.26/sysdeps/x86_64/tls_get_addr.S	2021-03-11 19:21:00.091940293 +0000
@@ -58,4 +58,67 @@
 	cfi_def_cfa (%rsp, 8)
 	ret
 END (__tls_get_addr)
+
+/* Userspace live-patching enabled libraries track all calls into the
+   library via the __ulp_entry function.  This tracking is per-thread,
+   so it uses thread-local variables, which require calls into
+   __tls_get_addr.  On the hot-path, few registers are used, however,
+   on the slow path, it calls a function in C, so the ABI must be
+   strictly followed.
+
+   This new function can be called from __ulp_entry without saving
+   caller-save registers. If the hot-path finds the address, it returns
+   quickly. Otherwise, it saves the registers that __ulp_entry did not
+   save, and calls the slow C function.  */
+ENTRY (__libpulp_tls_get_addr)
+	pushq	%rdx
+	mov	%fs:DTV_OFFSET, %RDX_LP
+	mov	GL_TLS_GENERATION_OFFSET+_rtld_local(%rip), %RAX_LP
+	/* GL(dl_tls_generation) == dtv[0].counter */
+	cmp	%RAX_LP, (%rdx)
+	jne	1f
+	mov	TI_MODULE_OFFSET(%rdi), %RAX_LP
+	/* dtv[ti->ti_module] */
+# ifdef __LP64__
+	salq	$4, %rax
+	movq	(%rdx,%rax), %rax
+# else
+	movl	(%rdx,%rax, 8), %eax
+# endif
+	cmp	$-1, %RAX_LP
+	je	1f
+	add	TI_OFFSET_OFFSET(%rdi), %RAX_LP
+	popq	%rdx
+	ret
+
+1:
+	/* Push everything that __ulp_entry had not.  */
+	pushq	%r10
+	pushq	%r9
+	pushq	%r8
+	pushq	%rsi
+	pushq	%rcx
+
+	/* On the slow path, align the stack.  */
+	pushq	%rbp
+	cfi_def_cfa_offset (16)
+	cfi_offset (%rbp, -16)
+	mov	%RSP_LP, %RBP_LP
+	cfi_def_cfa_register (%rbp)
+	and	$-16, %RSP_LP
+	call	__tls_get_addr_slow
+	mov	%RBP_LP, %RSP_LP
+	popq	%rbp
+	cfi_def_cfa (%rsp, 8)
+
+	/* Restore register before returning to __ulp_entry.  */
+	popq	%rcx
+	popq	%rsi
+	popq	%r8
+	popq	%r9
+	popq	%r10
+	popq	%rdx
+
+	ret
+END (__libpulp_tls_get_addr)
 #endif /* SHARED */

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File libpulp-0001-Non-ABI-compliant-__tls_get_addr-for-libpulp.patch of Package glibc (Revision fc8500aa4db0245927fcb5c0280c1a37)

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