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From:   Alexandre Chartre <alexandre.chartre@oracle.com>
To:     tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, hpa@zytor.com,
        x86@kernel.org, dave.hansen@linux.intel.com, luto@kernel.org,
        peterz@infradead.org, linux-kernel@vger.kernel.org,
        thomas.lendacky@amd.com, jroedel@suse.de
Cc:     konrad.wilk@oracle.com, jan.setjeeilers@oracle.com,
        junaids@google.com, oweisse@google.com, rppt@linux.vnet.ibm.com,
        graf@amazon.de, mgross@linux.intel.com, kuzuno@gmail.com,
        alexandre.chartre@oracle.com
Subject: [RFC][PATCH v2 02/21] x86/entry: Update asm_call_on_stack to support more function arguments
Date:   Mon, 16 Nov 2020 15:47:38 +0100
Message-Id: <20201116144757.1920077-3-alexandre.chartre@oracle.com>
In-Reply-To: <20201116144757.1920077-1-alexandre.chartre@oracle.com>
References: <20201116144757.1920077-1-alexandre.chartre@oracle.com>
Precedence: bulk

Update the asm_call_on_stack() function so that it can be invoked
with a function having up to three arguments instead of only one.

Signed-off-by: Alexandre Chartre <alexandre.chartre@oracle.com>
---
 arch/x86/entry/entry_64.S        | 15 +++++++++++----
 arch/x86/include/asm/irq_stack.h |  8 ++++++++
 2 files changed, 19 insertions(+), 4 deletions(-)

diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S
index cad08703c4ad..c42948aca0a8 100644
--- a/arch/x86/entry/entry_64.S
+++ b/arch/x86/entry/entry_64.S
@@ -759,9 +759,14 @@ SYM_CODE_END(.Lbad_gs)
 /*
  * rdi: New stack pointer points to the top word of the stack
  * rsi: Function pointer
- * rdx: Function argument (can be NULL if none)
+ * rdx: Function argument 1 (can be NULL if none)
+ * rcx: Function argument 2 (can be NULL if none)
+ * r8 : Function argument 3 (can be NULL if none)
  */
 SYM_FUNC_START(asm_call_on_stack)
+SYM_FUNC_START(asm_call_on_stack_1)
+SYM_FUNC_START(asm_call_on_stack_2)
+SYM_FUNC_START(asm_call_on_stack_3)
 SYM_INNER_LABEL(asm_call_sysvec_on_stack, SYM_L_GLOBAL)
 SYM_INNER_LABEL(asm_call_irq_on_stack, SYM_L_GLOBAL)
 	/*
@@ -777,15 +782,17 @@ SYM_INNER_LABEL(asm_call_irq_on_stack, SYM_L_GLOBAL)
 	 */
 	mov		%rsp, (%rdi)
 	mov		%rdi, %rsp
-	/* Move the argument to the right place */
+	mov		%rsi, %rax
+	/* Move arguments to the right place */
 	mov		%rdx, %rdi
-
+	mov		%rcx, %rsi
+	mov		%r8, %rdx
 1:
 	.pushsection .discard.instr_begin
 	.long 1b - .
 	.popsection
 
-	CALL_NOSPEC	rsi
+	CALL_NOSPEC	rax
 
 2:
 	.pushsection .discard.instr_end
diff --git a/arch/x86/include/asm/irq_stack.h b/arch/x86/include/asm/irq_stack.h
index 775816965c6a..359427216336 100644
--- a/arch/x86/include/asm/irq_stack.h
+++ b/arch/x86/include/asm/irq_stack.h
@@ -13,6 +13,14 @@ static __always_inline bool irqstack_active(void)
 }
 
 void asm_call_on_stack(void *sp, void (*func)(void), void *arg);
+
+void asm_call_on_stack_1(void *sp, void (*func)(void),
+			 void *arg1);
+void asm_call_on_stack_2(void *sp, void (*func)(void),
+			 void *arg1, void *arg2);
+void asm_call_on_stack_3(void *sp, void (*func)(void),
+			 void *arg1, void *arg2, void *arg3);
+
 void asm_call_sysvec_on_stack(void *sp, void (*func)(struct pt_regs *regs),
 			      struct pt_regs *regs);
 void asm_call_irq_on_stack(void *sp, void (*func)(struct irq_desc *desc),
-- 
2.18.4